Changing the Auto-Lock Time. Open the Settings app on your iPhone from the home screen or the Apps screen. Tap General and then tap the Auto-Lock option to view the automatic lock settings.Change the auto-lock time by tapping one of the options -- you can choose between one and five minutes.y default, your iPhone 6 locks automatically after one minute; its touchscreen locks and its display turns off. To prevent this, change the auto-lock time.