Altova XMLSpy - The XMLSpy XML Editor is a powerful tool for editing XML and related technologies. It is the only XML Editor with patented SmartFix validation, enterprise-grade editors, converters, debuggers, and code generators.
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
Liquid Studio - XML Tools Provider: XML Studio - Graphical XML Schema Editor.
Wondershare PDFelement - All-in-one PDF editor