A free app for Android, by Infinity Technologies Global.

All Document Reader and Viewer is a free fast and user-friendly app for reading and viewing PDF and other document formats.

You can open and view PDF files without needing to install additional software or connect to a computer. You can even view and edit PDF files on your phone, tablet, or laptop, without needing to use a computer.

You can also open and view PowerPoint, Excel, Word, Text, HTML, and other document formats.

This is a free, fast, and user-friendly app. 

All Document Reader supports many languages, including English, French, Spanish, Portuguese, Italian, Russian, German, Japanese, Chinese, and many more.