sim card

If you bought the 14 in the USA it uses an eSIM and no card.

This document will help you determine what size SIM your device takes: Learn which size SIM card your iPhone or iPad uses - Apple Support

Learn how to remove or transfer the SIM card in your iPhone or iPad (Wi-Fi + Cellular models). -->

Remove or switch the SIM card in your iPhone - Apple Support

Both phones use nanoSIMs.

However, you’ll need your carrier to re-provision your SIM to use the 5G capabilites of the “14”

Also consider moving to an eSIM if your carrier supports it. (Mandatory on U.S. 14s)

Yes, they both use a Nano SIM. However, if you wish to take advantage of 5G cellular capability, you may need a newer card, or you could use the built-in eSIM.