If you have a iPhone 13 or older, your device still has a physical SIM card. Here's a guide on how to remove it.

Push it towards your iPhone, and it will pop out. Remove or insert a SIM card and close the tray. Where is a SIM card slot on iPhone 14? If you have purchased an iPhone 14 in the United States, your ...

If you can't make a call or if you see an error message that your phone's SIM card is not working, there are several ways to troubleshoot the problem.