A free app for Android, by TVApp.

All Document Reader and Viewer for Android is a free app that can open and view a wide variety of document files on your phone or tablet, including PDF, DOC, DOCX, TXT, XLS, XLSX, PPT, PPTX, and more. The app also has the ability to read and view your email, as well as any attachments you receive. It is compatible with a wide variety of document formats and is very easy to use. It is designed to work offline, so you can access your files on your device even if you don’t have internet access.