How to disable screen auto lock in iPhone and iPad
Screen auto-lock is a feature that locks the screen of your iOS devices after a set period of time which is both battery-saving and provides privacy and security by preventing unauthorized access to your phone from an unlocked screen.
If you somehow have to disable the feature, perhaps temporarily due to lack of full background process support in iOS, you can do it via the Settings app.
Steps to disable screen auto lock in iPhone and iPad:
Open Settings by tapping the following icon on the home screen .
Tap on Display & Brightness.
Tap on Auto-Lock.
Choose the preferred timing. Never disables the display auto lock feature completely.