A free program for Android, by Office Tools- PDF Document Reader_Music Player MP3.

This app lets you open PDFs and read them. You can even search through them for a specific text or page number. If you have a long document with many pages, you can even scroll through it.

There is a simple and clean user interface. You don’t need to have any prior knowledge to use this app. You can open PDFs from your device or from Google Drive. You can also add multiple documents at once.

If you need to make changes to your document, you can do that easily. You can even add comments to them. This app is very useful for students.