Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Just to clarify, there's going to be big difference between actual text (searchable) and an image of text (not searchable).
For the former, depending on the app you're referring to it might require him to just copy-and-paste the text into a separate file, and then just use any text editor or word processor app to open that file and use the search function. Or if the app includes the functionality of saving to a text file that would be a lot simpler.
For the latter, when an image is involved (i.e. a jpg or tiff or whatever) it might be more involved. To get actual text, it would require printing out the image (in reasonably high resolution), and use an OCR utility to convert the printed image to text. And don't be surprised if the resulting text has errors, with text to text its all just digital copying but with image to text it's more similar to an analog to digital process, text to image to text.