// Install IronPdf with Nuget:  PM> Install-Package IronPdf
using IronPdf;

//The quickest way to cryptographically sign an existing PDF a digital certificate
new IronPdf.PdfSignature("Iron.p12", "123456").SignPdfFile("any.pdf");
// All done in 1 line of code!



//Advanced example for more control

// Step 1. Create a PDF
IronPdf.HtmlToPdf Renderer = new IronPdf.HtmlToPdf();
PdfDocument doc = Renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>");

// Step 2. Create a Signature.
// You may create a .pfx or .p12 PDF signing certificate using Adobe Acrobat Reader. 
// Read: https://helpx.adobe.com/acrobat/using/digital-ids.html
var signature = new IronPdf.PdfSignature("Iron.pfx", "123456");

// Step 3. Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com";
signature.SigningLocation = "Chicago, USA";
signature.SigningReason = "To show how to sign a PDF";
signature.LoadSignatureImageFromFile("handwriting.png");

//Step 4. Sign the PDF with the PdfSignature. Multiple signing certificates may be used
doc.SignPdfWithDigitalSignature(signature);

//Step 4. The PDF is not signed until saved to file, steam or byte array.
doc.SaveAs("signed.pdf");

' Install IronPdf with Nuget:  PM> Install-Package IronPdf
Imports IronPdf

'The quickest way to cryptographically sign an existing PDF a digital certificate
Call (New IronPdf.PdfSignature("Iron.p12", "123456")).SignPdfFile("any.pdf")
' All done in 1 line of code!



'Advanced example for more control

' Step 1. Create a PDF
Dim Renderer As New IronPdf.HtmlToPdf()
Dim doc As PdfDocument = Renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>")

' Step 2. Create a Signature.
' You may create a .pfx or .p12 PDF signing certificate using Adobe Acrobat Reader. 
' Read: https://helpx.adobe.com/acrobat/using/digital-ids.html
Dim signature = New IronPdf.PdfSignature("Iron.pfx", "123456")

' Step 3. Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com"
signature.SigningLocation = "Chicago, USA"
signature.SigningReason = "To show how to sign a PDF"
signature.LoadSignatureImageFromFile("handwriting.png")

'Step 4. Sign the PDF with the PdfSignature. Multiple signing certificates may be used
doc.SignPdfWithDigitalSignature(signature)

'Step 4. The PDF is not signed until saved to file, steam or byte array.
doc.SaveAs("signed.pdf")