Microsoft Lens - PDF Scanner is a free app for Android smartphones that enables you to convert and edit scanned documents. It also comes with a built-in document viewer and annotation tool. 

Scan documents with your camera or phone's built-in camera and then easily convert them into editable PDF files. 

If you're a student or a teacher, this app can help you save time and money. It can be used to easily scan documents at home, at school, and work. 

It's also great for people looking for a quick way to scan documents and make them searchable.

You can also use it to scan receipts and save them for easy access.