How to Create PDF Digital Signature in C# and VB.NET in Winform PDF?
Syncfusion Essential PDF is a .NET PDF library used to create, read, and edit PDF documents. Using this library, you can create a PDF digital signature with a custom appearance in C# and VB.NET.
Steps to create a PDF digital signature with a custom appearance programmatically:
- Create a new C# console application project.
- Install the Syncfusion.Pdf.WinForms NuGet packages as reference to your .NET Framework application from NuGet.org.
- Include the following namespaces in the Program.cs file.
C#
using Syncfusion.Pdf; using Syncfusion.Pdf.Graphics; using Syncfusion.Pdf.Security;
VB.NET
Imports Syncfusion.Pdf Imports Syncfusion.Pdf.Graphics Imports Syncfusion.Pdf.Security
- Use the following code snippet to create a PDF digital signature with a custom appearance.
// Creates a new PDF document
PdfDocument document = new PdfDocument();
// Adds a new page
PdfPageBase page = document.Pages.Add();
PdfGraphics graphics = page.Graphics;
// Creates a certificate instance from PFX file with the private key
PdfCertificate pdfCert = new PdfCertificate(@"PDF.pfx", "syncfusion");
// Creates a digital signature
PdfSignature signature = new PdfSignature(document, page, pdfCert, "Signature");
// Sets an image for the signature field
PdfBitmap signatureImage = new PdfBitmap(@"signature.png");
// Sets signature information
signature.Bounds = new RectangleF(0, 0, 200, 100);
signature.ContactInfo = "johndoe@owned.us";
signature.LocationInfo = "Honolulu, Hawaii";
signature.Reason = "I am the author of this document.";
// Create appearance for the digital signature
signature.Appearance.Normal.Graphics.DrawImage(signatureImage, signature.Bounds);
// Save the document
document.Save("DigitalSignature.pdf");
// Close the document
document.Close(true);
// This will open the PDF file so the result will be seen in the default PDF viewer
Process.Start("DigitalSignature.pdf");VB.NET
'Creates a new PDF document
Dim document As New PdfDocument()
'Adds a new page
Dim page As PdfPageBase = document.Pages.Add()
Dim graphics As PdfGraphics = page.Graphics
'Creates a certificate instance from PFX file with the private key
Dim pdfCert As New PdfCertificate("PDF.pfx", "syncfusion")
'Creates a digital signature
Dim signature As New PdfSignature(document, page, pdfCert, "Signature")
'Sets an image for the signature field
Dim signatureImage As New PdfBitmap("signature.png")
'Sets signature information
signature.Bounds = New RectangleF(0, 0, 200, 100)
signature.ContactInfo = "johndoe@owned.us"
signature.LocationInfo = "Honolulu, Hawaii"
signature.Reason = "I am the author of this document."
'Create appearance for the digital signature
signature.Appearance.Normal.Graphics.DrawImage(signatureImage, signature.Bounds)
'Save the document
document.Save("DigitalSignature.pdf")
'Close the document
document.Close(True)
'This will open the PDF file so the result will be seen in the default PDF viewer
Process.Start("DigitalSignature.pdf")A complete working sample can be downloaded from DigitalSignatureSample.zip.
By executing the program, you will get the PDF document as follows. 
Take a moment to peruse the documentation for adding a digital signature in a PDF document, where you will find other options like signing an existing document, adding a signature validation appearance based on the signature, enabling LTV PDF signatures, and adding a timestamp in the digital signature.
Refer here to explore the rich set of Syncfusion® Essential PDF features.
Starting with v16.2.0.x, if you reference Syncfusion® assemblies from the trial setup or the NuGet feed, include a license key in your projects. Refer to the link to learn about generating and registering the Syncfusion® license key in your application to use the components without a trial message.
Conclusion
I hope you enjoyed learning about how to create a PDF digital signature in C# and VB.NET in WinForms PDF.
You can refer to our WinForms PDF feature tour page to learn about its other groundbreaking feature representations. You can also explore our WinForms PDF documentation to understand how to create and manipulate data.
For current customers, you can check out our components from the License and Downloads page. If you are new to Syncfusion®, you can try our 30-day free trial to check out our other controls.
If you have any queries or require clarifications, please let us know in the comments section below. You can also contact us through our support forums or feedback portal. We are always happy to assist you!
