Document Reader: PDF DOC XLS is a free and easy-to-use app that allows you to read all kinds of office files, including PDF, WORD, EXCEL, PPT, TXT, PNG, JPG, RTF, and other formats. It supports all your devices and works offline. It's a versatile and powerful app and can handle a lot of documents at once. 

It's a great tool for people who need to read a lot of documents and files on the go. It supports all kinds of formats and works on Android phones and tablets. It has a very user-friendly interface and is very easy to use. You can also bookmark certain documents for easy searching.