This GroupDocs Documents Watermarking .NET SDK provides API access to this service. It provides a way to digitally add text and image watermarks on document formats including; Microsoft Office, OpenDocument, PDF, Email and more. It allows you to secure your sensitive documents from unauthorized access utilizing the GroupDocs.Watermark library. It also supports smart searching features to locate watermarks and remove them from documents. GroupDocs provides document manipulation APIs that allows you to view, convert, annotate, compare, sign, assemble and search documents in your applications.