Your PIN protects your SIM from unauthorised use if your mobile phone should get stolen. You can change your PIN to a PIN of your own choice making it easier to remember. Before you can change your PIN, you need to turn on use of PIN.
Tap Security & privacy.
Tap Additional settings.
Tap Set up SIM card lock.
Tap Change SIM PIN1.
Key in your current PIN and tap OK. The default PIN is 0000.