How to change Sim card from one phone to another phone

1. Remove the SIM card from the phone that it is in—>Remove or switch the SIM card in your iPhone or iPad - Apple Support
2. Insert the SIM card into the new phone.
3. Restart the new phone—>Restart your iPhone - Apple Support

Complication: If the SIM card from the old phone does not fit in the new phone contact the carrier to get a SIM card of the right size.

In addition to the above...

Check that the iPhone is unlocked.

How to unlock your iPhone for use with a different carrier - Apple Support

Problems with SIM transfers commonly run afoul of a carrier-locked iPhone.

If this iPhone was acquired carrier-locked, you may end up paying the remainder of any outstanding contract.

Contact your carrier for assistance.

Read the following article which will show you➔ How to Remove or Switch SIM cards in your iPhone.

Note that the SIM cards will need to be of the same size to fit from one iPhone to the other.

Axel F.