Stamp HTML onto Existing PDF C#

Whether you need to stamp, authorize, or add a watermark to a PDF, it is important you get the process right to convey correct usage restrictions. To stamp a PDF document correctly and efficiently in C#, we will use the IronPDF functions following the steps below.

Step 1

1. Install IronPDF to Your Project

Step number one is to install the IronPDF C# PDF Library into your project. Some may find it convenient to download directly while others may wish to navigate NuGet in order to access the Library. Either method is fine for this use, and you can use the software free for unlimited days within a development environment.

 PM > Install-Package IronPdf

How to Tutorial

2. Stamp a C# PDF

Stamping / Watermark

Stamping or Authorizing a PDF is really important for many document settings and use cases in .NET applications.

Now that we have IronPDF installed, it will be a simple function to add the stamp to your document.

In the below example, we have selected a PDF file. Using the “HtmlStamp()” function, on a note to use ‘BehindExistingPDFContent()’, the data which we select will get displayed on the BACK of a PDF, like a watermark.

Alternatively, with ‘OnTopOfExisitingPDFContent()’ , we will display the stamp ABOVE the PDF file.

Here is an example of how these functions could be incoporated into your project.

/**
Stamp CSharp PDF File
anchor-stamp-a-c-pdf
**/
using System.Windows.Forms;
using IronPdf;
using IronPdf.Editing;

namespace stamphtml
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //PDFs can be edited or amended by Stamping/Watermark new HTML content into the foreground or background.
            using PdfDocument pdf = PdfDocument.FromFile("sample.pdf");

            //Below are the two examples for Behind Text Stamp or Top of PDF Stamp

            //In BackgroundStamp, user can set his/her logo as a Watermark.
            var BackgroundStamp = new IronPdf.Editing.HtmlStamp() { Html = "<img src='logo.png' />", Width = 1000, Height = 50, Opacity = 50, Left = 68, Top = 25, ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.BehindExistingPDFContent};
            pdf.StampHTML(BackgroundStamp);

            //In ForegroundStamp, user can set his/her Text as a Verified.
            var ForegroundStamp = new IronPdf.Editing.HtmlStamp() { Html = "<h2 style='color:red'>Copyright 2020 IronPDF.com", Width = 50, Height = 50, Opacity = 50, Rotation = -45, ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.OnTopOfExistingPDFContent };
            pdf.StampHTML(ForegroundStamp);

            //We can SaveAs as our Stamping method is completed.
            pdf.SaveAs(@"C:\Users\Jugal\Desktop\Stamped.pdf");
        }
    }
}

/**
Stamp CSharp PDF File
anchor-stamp-a-c-pdf
**/
using System.Windows.Forms;
using IronPdf;
using IronPdf.Editing;

namespace stamphtml
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //PDFs can be edited or amended by Stamping/Watermark new HTML content into the foreground or background.
            using PdfDocument pdf = PdfDocument.FromFile("sample.pdf");

            //Below are the two examples for Behind Text Stamp or Top of PDF Stamp

            //In BackgroundStamp, user can set his/her logo as a Watermark.
            var BackgroundStamp = new IronPdf.Editing.HtmlStamp() { Html = "<img src='logo.png' />", Width = 1000, Height = 50, Opacity = 50, Left = 68, Top = 25, ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.BehindExistingPDFContent};
            pdf.StampHTML(BackgroundStamp);

            //In ForegroundStamp, user can set his/her Text as a Verified.
            var ForegroundStamp = new IronPdf.Editing.HtmlStamp() { Html = "<h2 style='color:red'>Copyright 2020 IronPDF.com", Width = 50, Height = 50, Opacity = 50, Rotation = -45, ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.OnTopOfExistingPDFContent };
            pdf.StampHTML(ForegroundStamp);

            //We can SaveAs as our Stamping method is completed.
            pdf.SaveAs(@"C:\Users\Jugal\Desktop\Stamped.pdf");
        }
    }
}

'''
'''Stamp CSharp PDF File
'''anchor-stamp-a-c-pdf
'''*
Imports System.Windows.Forms
Imports IronPdf
Imports IronPdf.Editing

Namespace stamphtml
	Partial Public Class Form1
		Inherits Form

		Public Sub New()
			InitializeComponent()

			'PDFs can be edited or amended by Stamping/Watermark new HTML content into the foreground or background.
			Using pdf As PdfDocument = PdfDocument.FromFile("sample.pdf")
	
				'Below are the two examples for Behind Text Stamp or Top of PDF Stamp
	
				'In BackgroundStamp, user can set his/her logo as a Watermark.
				Dim BackgroundStamp = New IronPdf.Editing.HtmlStamp() With {
					.Html = "<img src='logo.png' />",
					.Width = 1000,
					.Height = 50,
					.Opacity = 50,
					.Left = 68,
					.Top = 25,
					.ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.BehindExistingPDFContent
				}
				pdf.StampHTML(BackgroundStamp)
	
				'In ForegroundStamp, user can set his/her Text as a Verified.
				Dim ForegroundStamp = New IronPdf.Editing.HtmlStamp() With {
					.Html = "<h2 style='color:red'>Copyright 2020 IronPDF.com",
					.Width = 50,
					.Height = 50,
					.Opacity = 50,
					.Rotation = -45,
					.ZIndex = IronPdf.Editing.HtmlStamp.StampLayer.OnTopOfExistingPDFContent
				}
				pdf.StampHTML(ForegroundStamp)
	
				'We can SaveAs as our Stamping method is completed.
				pdf.SaveAs("C:\Users\Jugal\Desktop\Stamped.pdf")
			End Using
		End Sub
	End Class
End Namespace

3. Reliable Stamped Documents

Stamping a PDF will create more reliability & authenticity for a document. IronPDF makes it really simple for a developer to edit any PDF using the code above. We can see in the output below how the PDF file with the stamp provides more authenticity, and has numerous opportunities for use in your various .NET project needs.

Without Stamp

With Stamp

Library Quick Access

More API Reference

Get more documentation in the API Reference, providing other watermarking, authenticating, editing, and manipulating capabilities for your C# PDF projects.

More API Reference