Hi @Add_53063 welcome to 3Community. The standard pin code is usually 0000 or 1234 but if you've personalised it I won't have access to it. But not to worry 😊 you can reset it with your PUK code. Your phone will ask for your PUK code after you enter an incorrect sim pin 3 times.
You can get your PUK code by calling 1913 from another phone. Once you connect to the automated system enter your mobile number and select option 3.
If you have any questions or difficulties please let me know I'd be happy to help.
