Being able to add text or image watermark to PDF files is one of those handy things you can archive via program.
The only library required for the little program is iTextSharp. For those who haven’t used it yet, iTextSharp is a C# version of iText, which allows you to generate or manipulate PDFs.
So let’s cut the chitchat, and go straight to the code. By calling ‘AddTextWatermark’ or ‘AddImageWatermark’ function with required parameters supplied, you are ready to rock!