A free app for Android, by 9Office.

Document Viewer is a free all-in-one office suite app. It lets you open and view all documents on your Android phone. The app is designed to help you work on your documents and files, either at home or on the go. With it, you can view all your documents in one place, which makes it easier to process them.

You can open and view all types of files, such as Word, Excel, PowerPoint, PDF, Txt, Rtf, PPT, and more. The app supports many formats, including DOC, DOCX, XLS, TXT, PPT, and more. You can organize your files into different folders, which makes it easier to view them. You can also search for your files and open them in seconds.