Your phone might support using an eSIM (embedded SIM card), in addition to the physical SIM card. Contact your carrier for details.
If your carrier provided you with an eSIM:
Insert the SIM tool into the tray hole and gently push to pop it out.

To use one SIM card:

Or, to use two physical SIM cards (not available on all models):

Push the tray back into the phone.

You may need to erase your eSIM:
When you erase an eSIM, you remove the following capabilities from the phone:
Erasing the eSIM does not cancel your mobile data services. To cancel your services, contact your carrier.
To erase an eSIM:
To restore an eSIM you erased, contact your carrier.
If you’re having problems, try these troubleshooting steps.