https://wccftech.com/iphone-13-and-iphone-13-pro-feature-dual-esim-support/

iPhone 13 and iPhone 13 Pro are dual-SIM smartphones and you can have multiple eSIM phone numbers active at the same time.

The iPhone went dual-SIM with the iPhone XS and support for eSIM has been there for a long time. But this year, Apple is turning the heat up with eSIM. Rather than having a physical nano-SIM + eSIM configuration for dual-SIM support, you can use two eSIM phone numbers at the same time. In short, you can go all eSIM with the iPhone for dual-SIM mode and it will work like magic.