This article provides step-by-step instructions to adjust this setting and some benefits of using a shorter screen lock time.
The amount of idle time before this happens is your iPhone’s screen lock time setting.
To change your iPhone screen lock time, adhere to these instructions.

These instructions apply to all iPhones running recent versions of the iOS.
snag the amount of inactive time you want before the iPhone screen locks.
A shorter time is probably better (as discussed in the next section).

You should probably avoid choosingNeverunless you really understand the risks and benefits.
you might follow these instructions to change screen lock time on the iPad, too.
Why Should I Change the Screen Lock Time on My iPhone?
From there, you’re free to change the background and more.
To change your iPhone password, go toSettings>Passcode>Change Passcode.
TapPasscode Optionsto change if the passcode is numerically based or involves letters too.
If you forget your passcode, you’ll need to put your iPhone into Recovery Mode to restore it.
Tohide notifications on your iPhone lock screen, go toSettings>Notifications>Show Previews>When Unlocked.