C# .NET Core, Java, Python, PHP, Node.js, Python, JavaScript, C++, Android, Swift, Go, Ruby, Dart, Perl APIs to create and convert PDF, Word, Excel, PowerPoint, email, JPG, image, ZIP, and other formats on Windows, Linux, macOS & Android....excel 1 add watermark to excel sheet 1 Add watermark to PDF 2 add...scheme 1 combine all excel sheets into one 1 combine DOC files...