A free app for Android, by rtconsulting.

PicWriter is a free utility that lets you write text and shapes such as rectangles, circles, lines, and arrows directly on your photos. The PicWriter app is simple to use, with no ads or in-app purchases, and it works on many different kinds of photos, including images, vector images, and more.

To use PicWriter, you just need to import the image you want to write on and then choose the text style and size you want to write.

The best part of the app is that it is free, and you can download it easily from the Google Play store.