See what the code does PIN of the card SIM and learn step by step how you can disable the code SIM PIN from iPhone.
the code PIN of the card SIM is designed to protect both the data stored on the card and the use of the phone number by unauthorized persons in the event that the phone is lost or stolen. It is also very important that it is activated if you use banking applications. Most banking applications ask for authorization via a code "One Time Password” issued by SMS. In case of loss of the card SIM, if it has no code PIN, unauthorized persons may have access to sensitive data.
Even if on the device iPhone or on another smartphone there is a security code, if the card SIM it has no code PIN and is put into another phone, it can be used without restrictions.
However, for many users it is inconvenient to type the code PIN of the card SIM after restarting the device and therefore prefers disabling it.
How to deactivate the code SIM PIN from iPhone
To deactivate the code SIM PIN from iPhone, go to: “Settings”→“Mobile Data” (or Cellular) → SIM PIN. Here you have the option to deactivate SIM PIN or change PIN.

Slide the button SIM PIN, then enter the code PIN to disable. This way you can deactivate SIM PIN from iPhone.