Setting up a lock on your device will help keep your information secure. A screen lock will prevent others from getting into your device unless they have the necessary credentials. If your device is requesting a PUK code, you need to contact your carrier to unlock your device. Removing your security lock will allow anyone the ability to unlock your device.
1.
From the Home screen, tap Apps.
2.
Swipe to Settings.
3.
Tap Settings.
4.
Tap Lock screen.
5.
Tap Screen lock.
6.
Select your preferred screen lock and follow the onscreen prompts.