Signature Fields in the Viewer — TX Text Control .NET Server

Documents prepared for signing contain signature fields, and the Document Viewer turns them into signature boxes. With signature and initials boxes, required boxes and documents for several signers, you prepare documents and route them to one or more signers.

The signing process itself, with its settings and the endpoint that receives the signed document, is described in Digital Signatures. This page uses the same application.

From Signature Fields to Signature Boxes

A signature field is a frame in the document that holds the image of a signature, and it has a name. Documents get signature fields in three ways:

Users or your code insert them in the Document Editor; see Signature Fields in Document Editor.
ServerTextControl adds them on the server, as shown in Digitally Sign a PDF.
Signature lines of MS Word documents are imported as signature fields.

What a Signature Field Holds lists the formats that keep signature fields.

When the viewer loads a document with signature settings, it turns the signature fields whose names are listed in the signature boxes of the settings into signature boxes that users sign. Other signature fields of the document are shown, but they can't be signed in this session. This lets you send one document with several fields to several parties and activate only the fields of the current signer.

Each entry of signatureBoxes is a SignatureBox with these properties:

Property	Sets
name	The name of the signature fields that become signature boxes
style	What the box shows, a value of SignatureBoxStyle: `0` for the signature, `1` for the initials
signingRequired	Whether the box must be signed before the document can be submitted
signed	Whether the box is signed

Signature boxes confirm the complete document. Initials boxes are used to agree to specific parts, confirming that the signer has read them; they show the initials that users enter in the signature dialog.

Documents With Several Signers

In a document for several signers, give each signature field a name that identifies its signer. For example, a nondisclosure agreement has three fields:

Field name	Signed by
`sign_discloser`	The discloser, with a signature
`sign_vendor`	The vendor, with a signature
`init_vendor`	The vendor, with initials

The document is sent to each signer with signature settings that activate only that signer's fields. The following settings are those of the vendor, with a signature box and an initials box. They replace the settings of the loadDocument call in the view of Digital Signatures, which loads nda.docx instead of contract.docx:

await TXDocumentViewer.loadDocument(stored.data, stored.name, {
    showSignatureBar: true,
    ownerName: "Paul Paulsen",
    signerName: "Tim Typer",
    signerInitials: "TT",
    uniqueId: "NDA-2026-001",
    redirectUrlAfterSignature: window.location.origin + "/Signature/SignDocument?signer=vendor",
    signatureBoxes: [
        { name: "sign_vendor", signingRequired: true, style: 0 },
        { name: "init_vendor", signingRequired: true, style: 1 }
    ]
});

Only sign_vendor and init_vendor become signature boxes; sign_discloser stays inactive in this session.
style: 1 makes init_vendor an initials box.
The query string of redirectUrlAfterSignature tells the endpoint which signer submitted the document.

With these settings, the vendor sees two boxes to sign, the small initials box in the text and the signature box, each with a SIGN HERE marker. The discloser's field is shown as an empty signature line without a marker:

A nondisclosure agreement in the Document Viewer with the signature bar, a small initials box after "Initials of the Vendor", the inactive gray signature line of the discloser and the yellow signature box of the vendor, both boxes marked SIGN HERE

The endpoint receives the signer as a parameter of its action, and SignatureData.SignatureBoxes contains the boxes the signer submitted as .NET SignatureBox objects with Name, Style and SigningRequired. Collect Signatures From Several People in Multiple Signatures shows the action that keeps the document between the signers and certifies it after the last one. A signature field keeps its own certificate and validation status, which makes signature fields suitable for several signers.

Check the Signature Fields of a Document

Before a document is sent to signers, check on the server that it contains the signature fields your process expects: ServerTextControl.SignatureFields lists the fields of the main text, and SignatureFieldCollection.GetItem returns null for a name the document doesn't contain. Signature Fields in Digital Signatures describes both.

Next Steps

Digital Signatures: the signing process and the endpoint.
Signature Fields in Document Editor: insert and name signature fields.
Multiple Signatures: sign PDF documents with several certificates.