# Digitally Sign a PDF

> Sign PDF files from Windows Forms with a .pfx certificate and DigitalSignature: invisible signatures, trusted timestamps and a signature field with an image.

- **Product:** TX Text Control .NET for Windows Forms
- **Section:** Documentation
- **Kind:** Topic
- **Path:** TX Text Control .NET for Windows Forms > Getting Started > PDF Processing > Digitally Sign a PDF
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/llms-full.txt

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## On This Page

- [How PDF Signing Works](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#how-pdf-signing-works)
- [Prerequisites](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#prerequisites)
- [Create a Self-Signed Certificate for Testing](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#create-a-self-signed-certificate-for-testing)
- [Sign the Whole Document](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#sign-the-whole-document)
- [Add a Trusted Timestamp](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#add-a-trusted-timestamp)
- [Sign a Signature Field](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#sign-a-signature-field)
- [Next Steps](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/sign/#next-steps)

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## Nearby

- **Previous:** [Create a PDF Form](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/getting-started/pdf/form/llms.txt)
- **Next:** [Document Editor](https://docs.textcontrol.com/tx-text-control-dotnet-winforms/document-editor/llms.txt)