How to Make the Keyboard Buttons Bigger on an iPhoneby Ryan Menezes ; Updated August 29, 2017
You need good eyes and quick fingers to type on an iPhone as fast as you could on a computer. Though iPhones have been steadily increasing in size, they're still far smaller than full computer keyboards or even tablet PCs. If you find your iPhone's buttons too small, you can enlarge them by using the phone's Zoom feature. Zooming magnifies everything that the iPhone displays, including the keyboard and the rest of the screen's text or images.
Rotating the iPhone
Rotate the iPhone 90-degrees to put it in landscape mode. Provide the app you are using supports this mode, the keyboard should appear larger.
Tap the "Settings" icon on your iPhone's home screen and select "General."
Tap "Accessibility" to open your accessibility screen.
Tap the slider labeled "Zoom" and slide it from "Off" to "On."
When using the keyboard (or any other feature), zoom in by double-tapping the screen with three fingers. Zoom back out by double-tapping again with three fingers.