Turn on your iPhone and complete the initial setup
Connect to Wi-Fi
Insert your physical SIM card if your iPhone uses one
Or scan your carrier’s eSIM QR code if you are using eSIM
Or transfer your cellular plan from your old iPhone during setup
Open Settings
Tap Cellular or Mobile Data
Tap Set Up Cellular or Add eSIM
Follow the on-screen prompts from your carrier
Sign in to your carrier account if required
Confirm your phone number and plan details
Restart your iPhone if prompted
Test calling, texting, and mobile data
Turn Cellular Data on in Settings if it is off
Enable roaming if needed for travel
Contact your carrier if activation fails