To change the type of security required to unlock your phone after it goes to sleep:
Touch Screen lock and select the type of lock you want:
Swipe: Prevents accidental dialing but doesn't secure the phone. Swipe
up. Don't select this if you want to use a trusted Bluetooth device.
Some of these options aren't available if you added a VPN or a work (corporate) email account to your phone.
If you're using a PIN, password, or pattern, you can:
You can hide your password or pattern to prevent others from viewing it when you unlock your screen.
If you forgot your PIN, pattern, or password, try these troubleshooting steps.