"Trouble reading a menu? On an iPhone, go to Settings > Accessibility > Magnifier. Flip it to on, then when you click the home button three times, the camera will open as a magnifying lens with a zoom function."
It worked for my iPhone. The paragraph goes on to give instructions for Android phones, too.
* From the February 2021 issue of Reader's Digest, page 32
"Android users, turn the feature on in Settings > Accessibility > Vision > Magnification, then open the camera and tap the screen three times."