1. Find "Set up SIM card lock"
Slide your finger downwards starting from the top of the screen.
Press the settings icon.
Press Lock screen and security.
Press Other security settings.
Press Set up SIM card lock.
2. Turn use of PIN on or off
Press the indicator next to "Lock SIM card" to turn the function on or off.
Key in your PIN and press OK.
3. Return to the home screen
Press the Home key to return to the home screen.