In iOS 12, a new feature called SIM PIN was introduced. SIM PIM allows you to enter a PIM to lock your SIM card. Whenever you restart your device or pop your SIM card out and place it in a new device, you’ll need to enter the SIM PIN to access cellular functionality. This may be beneficial if your iPhone is stolen. It can prevent people from just popping out your SIM card, placing it into a device that they have on hand, and using your cellular line to make calls and texts.
