Previously, zoom features were either nonexistent or difficult to use.
The Apple zoom feature works on photos, web pages, and anyappthat supports the pinch-zoom gesture.
These directions apply generally to all iPad and iPhone models running iPadOS 13 and later andiOS13 and later.

If it helps you remember, think of your fingers pinching a piece of paper.
The same idea applies here.
Use the Accessibility Zoom Setting
In some cases, the pinch-to-zoom feature doesn’t work.

Go toAccessibility>Zoom.
Tap theZoomtoggle switch to make it green and turn it on.
Double-tap the screen with three fingers to enable or disable zoom.
To disable it permanently, repeat the steps above and toggleZoomto theoffposition.