A free app for Android, by Pion Tech.

Magnifier – Magnifying Glass is a free magnifying glass app for Android phones. You can use it to magnify texts, images, and many other things. 

The magnifier glass can magnify objects by using the built-in camera on your phone. To use the magnifier, you can either select a particular object or zoom in on an area of the object you want to see more clearly.

You can also use the magnifier to read the content of a text or book. You can use it to read serial numbers, get information from receipts, and read the content of a menu, for example.