On an iOS device use the Notes app to scan a document
If you would like to scan a document with your phone, try using the Notes app on your iOS device. Once you open the Notes app select the square with pencil (bottom right of screen) and then select the circle with a plus in it. You can then scan your document and save it to your camera roll, send in a text, as well as many other options.
Embedded below is a GIF followed by a 37 second YouTube tutorial.