Adding a digital electronic signature to a PDF is simpler than you might expect, and it guarantees the document’s authenticity. In this tutorial we’ll show you how to add a digital signature to PDF in C# step by step, featuring a hands‑on example of digital signature in C#. You’ll receive clear, actionable instructions for signing PDF files with a digital signature, plus ready‑to‑use sample code to jump‑start your implementation.

Steps to Add Digital Signature to PDF in C#

1. Install Conholdate.Total for .NET package from the NuGet in the .NET application
2. Include a reference to the GroupDocs.Signature namespace for implementation of a digital signature
3. Create an instance of the Signature class and load the input PDF document
4. Create an instance of the DigitalSignOptions class with the required certificate and its password
5. Invoke the Sign method of the Signature class and pass the output PDF file path along with the DigitalSignOptions object

By following these steps, you can easily create a C# digital signature with just a few lines of code. First, install the package from NuGet and add the required namespace to your code. Then, create a Signature object to load your PDF file, set up a DigitalSignOptions object with your certificate. Finally, add the digital signature to your PDF and save it by calling the Sign method.

Code to Add Digital Signature to PDF in C#

Having walked through each step, you now know how to add a digital signature in c#, including key settings like the signature’s left and top coordinates. Treat the sample code as a robust starting point, then enrich it with extra properties—Contact, Reason, Location, Visible, and more—to customize the signature exactly as you require.

By following this guide, you now know how to programmatically add a digital signature to a PDF using C#. Ready to take your PDF processing to the next level? Check out our tutorial on how to convert PDF to HTML using C# for more powerful transformations.