GroupDocs.Watermark for .NET is a powerful API for managing watermarks in the various documents formats such as PDF, DOCX/DOC/RTF, PPTX/PPT, Xlsx/XLS, JPG, PNG, TIFF, GIF and many others....PDF, DOCX/DOC/RTF, PPTX/PPT, XLSX/XLS, JPG, PNG, TIFF, GIF and...