Open the Settings app
Tap Display & Brightness
Tap Display Zoom
Select Zoomed
Tap Set
Restart the iPhone if prompted
Use the iPhone in landscape mode for a larger keyboard in supported apps
Turn on one-handed keyboard if needed by pressing and holding the globe or emoji key, then selecting the left or right keyboard option
Install a third-party keyboard app with larger keys from the App Store
Adjust text size in Settings > Display & Brightness > Text Size to make some keyboard labels easier to see