What is eSIM and How to Activate It 

What is eSIM on iPhone?
eSIM is an electronic SIM that allows you to activate a cellular plan from your carrier without having to use a physical SIM card. This means you can have two phone numbers on your iPhone, or use a different cellular plan when you travel.
How to activate eSIM on iPhone
To activate eSIM on your iPhone, you will need to:
Make sure your iPhone supports eSIM. The following iPhones support eSIM:
iPhone XR
iPhone XS
iPhone 11
iPhone 12
iPhone 13
iPhone SE (3rd generation)
iPhone 14
Contact your carrier and request an eSIM plan.
Once you have received your eSIM plan, follow these steps to activate it:
Open the Settings app on your iPhone.
Tap Cellular.
Tap Add Cellular Plan.
Scan the QR code provided by your carrier.
Follow the on-screen instructions to activate your eSIM plan.
I hope this helps!