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 to be able to unlock your device.
From the Home screen, drag down the Notification panel.
Drag down the Quick settings panel.
Tap the Settings icon.
Scroll to Security.
Tap Screen lock.
Note: For this tutorial, we're showing how to set up a PIN. You can select a different type of security, but steps may vary based on what you choose.
Enter your PIN.
Note: Your PIN must be at least 4 numbers long.
Confirm your PIN.
Select a notification preference.
Note: Tap Hide sensitive content to prevent the content of emails, texts and other notifications from appearing on the Lock screen. You'll be notified that you have a new message, but not shown what the message contains.