GroupDocs.Watermark library provides the ability to manipulate different watermark types such as TextWatermark, ImageWatermark. These watermarks could be added to documents, updated, removed, or searched inside already watermarked documents. Our product also provides information about document type and structure - file type, size, page count, etc. and generates document page previews based on provided options.
Here are the main GroupDocs.Watermark API concepts:
Watermarker is the main class that contains all the required methods for manipulating document watermarks....to add watermark to PDF, DOC, DOCX, PPT, PPTX, XLS, XLSX, emails...