Use Pinch Gestures to Zoom In and Out 

To zoom in on a photo or web page, press on the screen with your index finger and thumb leaving only a small amount of space between the two fingers. Keep your finger and thumb on the screen, then move your fingers away from each other, expanding the space between them. As your fingers move apart, the screen zooms in. To zoom out, do the reverse: Move your thumb and index finger toward each other while keeping each pressed to the screen. Any two fingers can be used to zoom in and out on an iPhone or iPad, but for most people, the thumb and index finger make the most sense.

Use the Accessibility Zoom Setting

In some cases, the pinch-to-zoom feature doesn’t work. An app might not support the gesture, or a web page may have code that is running or a stylesheet setting that prevents the page from being expanded. The iPad accessibility features include a zoom that always works no matter if you’re in an app, on a web page, or viewing photos. The feature isn’t activated by default, so you must turn it on in the Setting app: After you activate zoom on your iPad or iPhone, you’ll immediately see the magnifying glass, like shown here on an iPad. Press and hold the anchor/bar at the bottom of the zoom window to move it around the screen and see everything zoomed up. You can also press-and-drag three fingers, which might be preferred when zooming with this tool on a smaller screen like an iPhone. Double-tap the screen with three fingers to enable or disable zoom. To disable it permanently, repeat the steps above and toggle Zoom to the off position.