# AcroForms

> Create fillable PDF forms from form fields and DOCX templates, protect them with permissions and read them with the AcroForms classes of GetAcroFormFields.

- **Product:** TX Text Control .NET Server
- **Section:** Documentation
- **Kind:** Topic
- **Path:** TX Text Control .NET Server > PDF Processing > PDF Forms > AcroForms
- **3821 words**
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/acroforms/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/acroforms/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/acroforms/llms-full.txt

---

When a customer fills in a PDF form in Adobe Acrobat Reader or a browser, they type into AcroForm fields, the interactive form fields of the PDF format. TX Text Control writes these fields when a document with form fields is saved as PDF, and it reads them from the PDF documents that come back. Knowing what ends up in the PDF, and how the fields look to your code when you read them, helps you design forms whose data you can process reliably.

The form field types of TX Text Control and the code that inserts them are described in [Form Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/document-processing/form-fields/llms-full.txt) in Document Processing. Processing the values of returned forms is the subject of [Import Form Data](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/import-data/llms-full.txt).

### What AcroForms Are

Interactive forms in the PDF format, also known as AcroForms, are the common standard for PDF forms. An AcroForm field is a text field, a check box, a radio button, a push button or a choice field such as a drop-down list. Each field has a name that identifies its value, a position in the document and, optionally, a tooltip.

TX Text Control works with AcroForms in both directions:

- **Creating.** Since version 28.0, form fields are converted into PDF form fields when a document is saved as PDF.
- **Reading.** Since version 29.0, [Forms.GetAcroFormFields](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/forms/getacroformfields-method/llms-full.txt) returns the fields of a PDF document with their values. You call it with a file name or a byte array and don't create a `ServerTextControl` for it.

The TX Text Control form field types are text form fields, check boxes, drop-down lists, combo boxes and date form fields. There are no radio buttons or push buttons among them, so TX Text Control doesn't create these fields, but it reads them from PDF documents created with other tools.

### Create a Fillable PDF Form

All form field types are exported as the corresponding AcroForm fields, with their names and values. A PDF reader recognizes the saved document as a form, and values that your code set before saving are already filled in and can be changed. The following program loads the order form that [Create a Fillable Form](https://docs.textcontrol.com/tx-text-control-dotnet-server/document-processing/form-fields/#create-a-fillable-form) creates, saved as *Documents/order-form.tx*, gives each field a description, saves it as PDF and lists the AcroForm fields of the result:

```csharp
using TXTextControl;
using TXTextControl.DocumentServer.PDF;
using TXTextControl.DocumentServer.PDF.AcroForms;

using (ServerTextControl tx = new ServerTextControl())
{
    tx.Create();
    tx.Load("Documents/order-form.tx", StreamType.InternalUnicodeFormat);

    // Written in full, because the AcroForms namespace has a FormField class, too
    foreach (TXTextControl.FormField field in tx.FormFields)
    {
        field.DescriptiveText = field.Name switch
        {
            "Customer" => "Name of the customer",
            "Product" => "Product to order",
            "InvoiceDate" => "Date of the invoice",
            "TermsAccepted" => "Customer accepts the terms and conditions",
            _ => field.DescriptiveText
        };
    }

    tx.Save("Documents/order-form.pdf", StreamType.AdobePDF);
}

foreach (var field in Forms.GetAcroFormFields("Documents/order-form.pdf"))
{
    // Derived classes first: a radio button is a check box, a list box is a combo box
    string details = field switch
    {
        FormTextField textField => $"text \"{textField.Value}\"",
        FormRadioButton radioButton => $"radio button, checked: {radioButton.IsChecked}",
        FormCheckBox checkBox => $"check box, checked: {checkBox.IsChecked}",
        FormListBox listBox => $"list box, value \"{listBox.Value}\"",
        FormComboBox comboBox => $"combo box, value \"{comboBox.Value}\"",
        FormButton => "push button",
        _ => ""
    };

    Console.WriteLine($"{field.FieldName}: {details}, tooltip \"{field.AlternateFieldName}\"");
}
```

The code works as follows:

- [DescriptiveText](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol/formfield/descriptivetext-property/llms-full.txt) describes a form field for screen readers. In the blog article [Designing the Perfect PDF Form with TX Text Control in .NET C#](https://www.textcontrol.com/blog/2025/12/16/designing-the-perfect-pdf-form-with-tx-text-control-in-dotnet-csharp/), these descriptions appear as tooltips in Acrobat Reader and come back as `AlternateFieldName`.
- `StreamType.AdobePDF` turns the form fields into AcroForm fields. The [Name](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol/textfield/name-property/llms-full.txt) of a form field becomes the name of the AcroForm field.
- `GetAcroFormFields` returns an array of field objects. The `switch` expression tests the derived classes first, because [FormRadioButton](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formradiobutton/llms-full.txt) derives from [FormCheckBox](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formcheckbox/llms-full.txt) and [FormListBox](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formlistbox/llms-full.txt) from [FormComboBox](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formcombobox/llms-full.txt).

Two practices from the blog article make a form reliable: form fields placed in table cells keep their size and position in Acrobat Reader, and names that describe the content, such as `Customer` instead of a generated name, let your code map the values to its data model.

The form of that article, opened in Adobe Acrobat Reader, keeps the layout it has in TX Text Control. Its fields sit in table cells, and the reader highlights them as fillable:

![Address Change form created with TX Text Control and opened in Adobe Acrobat Reader, with fillable fields for the name, address and phone numbers in table cells and a signature field](https://docs.textcontrol.com/assets/img/tx-text-control-dotnet-server/acroform-in-acrobat.4fb7d014.webp)

### Turn a DOCX Form Into a Fillable PDF

Forms designed in MS Word contain content controls or legacy form fields. Loaded into TX Text Control, they become form fields, and saved as PDF, they become AcroForm fields. The following program converts *Documents/form.docx* into a PDF that readers can fill in and print, but not change otherwise:

```csharp
using TXTextControl;

LoadSettings loadSettings = new LoadSettings()
{
    // Content controls and legacy form fields become form fields
    ApplicationFieldFormat = ApplicationFieldFormat.MSWordTXFormFields
};

using (ServerTextControl tx = new ServerTextControl())
{
    tx.Create();
    tx.Load("Documents/form.docx", StreamType.WordprocessingML, loadSettings);

    SaveSettings saveSettings = new SaveSettings()
    {
        MasterPassword = "owner1234",
        DocumentAccessPermissions = DocumentAccessPermissions.AllowAuthoringFields |
                                    DocumentAccessPermissions.AllowHighLevelPrinting
    };

    tx.Save("Documents/form.pdf", StreamType.AdobePDF, saveSettings);
}
```

The code works as follows:

- [ApplicationFieldFormat](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol/loadsettings/applicationfieldformat-property/llms-full.txt) `MSWordTXFormFields` imports the form fields of the DOCX file as form fields and all other MS Word fields, such as merge fields, as application fields. With the default value `None`, form fields are imported as form fields as well.
- [DocumentAccessPermissions](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol/savesettings/documentaccesspermissions-property/llms-full.txt) `AllowAuthoringFields` allows filling in existing form fields, and `AllowHighLevelPrinting` allows printing. The permissions only take effect together with a [MasterPassword](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol/loadsavesettingsbase/masterpassword-property/llms-full.txt). Without a user password, everyone can open the form.

[Protect a PDF With Passwords and Permissions](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/creation/#protect-a-pdf-with-passwords-and-permissions) lists all permissions. The blog article [Convert MS Word DOCX to PDF with Form Fields in C# .NET](https://www.textcontrol.com/blog/2025/02/26/convert-ms-word-docx-to-pdf-with-form-fields-in-csharp-dotnet/) converts a DOCX form with all form field types.

In the PDF of that article, the legacy form fields and the content controls of the Word document are fillable text fields, check boxes and drop-down lists:

![PDF converted from a Word document in Adobe Acrobat, whose legacy form fields and content controls became a fillable text field, a check box and a drop-down list each](https://docs.textcontrol.com/assets/img/tx-text-control-dotnet-server/docx-form-fields-pdf.309eb74e.webp)

### Other Ways to Create PDF Forms

- **In the Document Editor,** users insert form fields in the browser, and `saveDocument` with `AdobePDF` saves the form as PDF, as [Form Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/document-editor/form-fields/llms-full.txt) in Document Editor describes.
- **With a mail merge,** `MailMerge.FormFieldMergeType` `Preselect` fills the form fields of a template with data and keeps them fillable, while `Replace` replaces them with the values, as [Merge Form Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/mail-merge/fields/#merge-form-fields) shows.
- **From an HTML form,** the blog article [Create Fillable PDFs from HTML Forms in C# ASP.NET Core Using a WYSIWYG Template](https://www.textcontrol.com/blog/2026/03/17/create-fillable-pdfs-from-html-forms-in-csharp-aspnet-core-using-a-wysiwyg-template/) builds the HTML inputs from the form fields of a template and merges the posted values into a fillable PDF.

### Where Users Fill In the Form

- **Adobe Acrobat Reader** and other PDF readers that support form fields.
- **Google Chrome** fills in AcroForm fields since version 85 and downloads the PDF with the entered values.
- **The Document Viewer** displays PDF forms with PDF.js, lets users fill them in and sign them and saves the values into the PDF, as [Form Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/document-viewer/form-fields/llms-full.txt) in Document Viewer describes.

### The AcroForms Classes

`GetAcroFormFields` returns an array of [FormField](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formfield/llms-full.txt) objects of the `TXTextControl.DocumentServer.PDF.AcroForms` namespace. Each object is of the class that fits its field:

| Class | Field in the PDF | Members |
|---|---|---|
| `FormField` | The base class of all fields | [FieldName](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formfield/fieldname-property/llms-full.txt), [AlternateFieldName](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formfield/alternatefieldname-property/llms-full.txt), [FieldType](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formfield/fieldtype-property/llms-full.txt), [Bounds](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formfield/bounds-property/llms-full.txt) |
| [FormTextField](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formtextfield/llms-full.txt) | Text field | [Value](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formtextfield/value-property/llms-full.txt) |
| `FormCheckBox` | Check box | [IsChecked](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formcheckbox/ischecked-property/llms-full.txt) |
| `FormRadioButton` | Radio button, derived from `FormCheckBox` | `IsChecked` |
| [FormButton](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formbutton/llms-full.txt) | Push button | None |
| [FormChoiceField](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/llms-full.txt) | The base class of choice fields | [Value](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/value-property/llms-full.txt), [Options](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/options-property/llms-full.txt), [CanEdit](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/canedit-property/llms-full.txt), [MultiSelect](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/multiselect-property/llms-full.txt), [Sort](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/sort-property/llms-full.txt), [DoNotSpellCheck](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/donotspellcheck-property/llms-full.txt), [CommitOnSelChange](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-pdf/acroforms-formchoicefield/commitonselchange-property/llms-full.txt) |
| `FormComboBox` | Combo box, derived from `FormChoiceField` | The members of `FormChoiceField` |
| `FormListBox` | List box, derived from `FormComboBox` | The members of `FormChoiceField` |

What the members contain:

- **`FieldName`** is the name of the field, and **`AlternateFieldName`** its alternate name, which Acrobat shows as the tooltip.
- **`FieldType`** is a value of the [FieldType](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver/pdf-acroforms-fieldtype/enumeration/llms-full.txt) enumeration: `Tx` for a text field, `Btn` for a button, `Ch` for a choice field or `Sig` for a signature field. Signature fields are processed with the classes described in [Signature Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/digital-signatures/signature-fields/llms-full.txt).
- **`Bounds`** is the rectangle of the field in the document.
- **`Options`** lists the items of a choice field and **`Value`** holds the selected value. **`CanEdit`** and **`MultiSelect`** tell whether users can type their own value or select several items.

The `TXTextControl` namespace has a `FormField` class, too, for the form fields of a document. When a file uses both namespaces, write one of the class names in full, as the program above does.

### Forms in PDF/A and PDF/UA Documents

- **Accessibility.** A form in an accessible PDF needs a `DescriptiveText` for every form field, as [PDF/UA](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/pdf-ua/llms-full.txt) describes.
- **Archiving.** PDF/A doesn't allow encryption, so permissions can't protect a PDF/A form. Forms that users fill in are delivered as PDF, and the filled result can be flattened and archived, as [Flatten Forms](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/flatten/llms-full.txt) describes.

### Next Steps

- [Import Form Data](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/import-data/llms-full.txt): read the values of filled PDF forms into your application.
- [Export XFDF](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/export-xfdf/llms-full.txt): exchange form data as XFDF.
- [Flatten Forms](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/flatten/llms-full.txt): replace form fields with their values before archiving.
- [Form Fields](https://docs.textcontrol.com/tx-text-control-dotnet-server/document-processing/form-fields/llms-full.txt): create form fields in code.

---

## Nearby

- **Previous:** [PDF Forms](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/llms-full.txt)
- **Next:** [Import Form Data](https://docs.textcontrol.com/tx-text-control-dotnet-server/pdf/forms/import-data/llms-full.txt)