OPPO A57s
Turn use of PIN on or off
The PIN protects your SIM from unauthorised use if your phone should get stolen. If use of PIN is turned on, it needs to be keyed in when you turn on your phone.
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Password & security.
Press System security.
Press SIM card lock.
Press the required SIM.
Press the indicator next to "Lock SIM Card" to turn the function on or off.
Key in your PIN and press the confirm icon.
Press the Home key to return to the home screen.
1. 1. Find "SIM card lock"
2. 2. Turn use of PIN on or off
3. 3. Return to the home screen