How can I identify the carrier of my iPhone?

would you like to know the service provider from your phone number or have you bought your phone carrier-locked (like at AT&T)?

if you simply would like to identify your service provider, follow these steps:

1. go into settings
2. tap „cellular“
3. Underneath „personal hotspot“, you should find some options like WiFi-calling. Above that, there should be a text showing your carrier

or

1. go to the control center
2. next to your signal strength, there should also be a text showing your carrier

I can only suspect you have purchased a used phone that is Carrier Locked and you do not know the carrier because it does not have a SIM card. There is nothing on the device that will identify the carrier it is locked to without the SIM card and even if you knew the carrier, they will most likely not remove the lock if you are not currently a customer of theirs.

The device may still be part of a subsidized agreement to the carrier and they will not give you any information about the account that has the device locked. They won't even tell you if the obligations for that account have been meant that would allow it to be unlocked.