I helped a relative out with this issue recently and since it’s such a super-simple fix, I thought I’d show you how to take care of it. Her screen was locking when in not in use much too quickly to suit her taste and she wanted to know if I knew how to fix it. Fortunately, I was able to do it in a few seconds. (Which is great because there’s nothing worse than being a tech writer that has no clue how to fix a tech problem.)
Start by tapping the settings icon on your iPhone.
Scroll down and tap on Display and Brightness.
Then choose Auto-lock and tap on the time displayed.
Adjust your phone to lock after anywhere from 30 seconds to 5 minutes of inactivity or set it to never lock. Never locking is not suggested for security purposes.