.NET library that adds, edits, and removes annotations and markup — area and shape annotations, text highlight/underline/strikeout, watermarks, image and link stamps, and threaded comments — on PDF, Word, Excel, PowerPoint, images, CAD, Visio, and email Files. No Microsoft Office or Adobe Acrobat required.... Supported File Formats GroupDocs.Annotation...Annotation supports a wide range of file formats. For a complete list...