Open the Settings app
Tap Display & Brightness
Tap Display Zoom
Select Larger Text
Tap Done
Restart your iPhone if needed
Open Settings
Tap Accessibility
Tap Display & Text Size
Turn on Bold Text if desired
Open the keyboard in any app
Rotate your iPhone to landscape mode for a larger keyboard
Use one-handed keyboard settings if needed
Open Settings
Tap General
Tap Keyboard
Tap One-Handed Keyboard
Select Off, Left, or Right
Use a third-party keyboard app with larger keys if needed