Steps to enable Zoom Smart Typing on an iPhone
1) Go to 'Settings' in your iPhone
2) Tap 'Accessibility'
3) Tab 'Zoom'
4) Enable 'Zoom', 'Follow Focus' and 'Smart Typing' options
You can also access the 'Zoom' settings directly with Siri as below, to enable Zoom Smart Typing
1) Bring Siri by saying 'Hey Siri' or press and release the right-side button on your iPhone
2) Say 'Go to Zoom Settings'
3) It will take you to 'Accessibility' screen
4) Tab 'Zoom'
5) Enable 'Zoom', 'Follow Focus' and 'Smart Typing' options
Turning on ‘Smart Typing’ enables Window Zoom when the keyboard appears, and allows you to move the text window with a slider and zoom the text. It's very convenient to zoom the text while you are typing.