How to remove the SIM card from your iPhone to replace it or throw it away

To remove the SIM card from your iPhone, you'll need to eject the SIM card tray with a special tool or paperclip.

How to unlock an iPhone from your current carrier and switch it to a new one

To unlock your iPhone from its carrier, you'll likely need to contact your carrier directly to cancel your contract.
CCM

SIM card: what it is, how to remove, install, in an iPhone

What is a SIM card used for? A SIM card, or a subscriber identity module/subscriber identification module, is a tiny memory card that contains unique information and is linked to a particular network ...
PC Magazine

Physical SIM Cards Are Gone. Here's How to Add an eSIM to Your iPhone 16

Apple removed the physical SIM slot for the iPhone 14, 15, and 16 in the US. If you're travelling out of the country or need a separate work line, here’s how to get connected using an eSIM. Lance is ...