These steps show you how to do it: Power down your phone and then insert the new SIM card. If you have multiple ... To ...
To find this number on an iPhone, go to Settings > General ... A simple way to check if your device is unlocked is to insert ...
Check SIM Card in iPhone Settings: Insert the SIM into your iPhone. Once your iPhone recognizes the SIM card, it will figure out the attached phone number (if there is one). Scroll down and tap Phone.