iPhone settings is saying sim lock

To be able to use any SIM across the globe you must have "No SIM Restriction" against Network Provider Lock. Please refer to the pic below.

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

Device Unlocking Policies | Verizon Privacy Policy

Unlock a Phone or Device - AT&T Device Unlock Portal

Unlocking your Sprint device - T-Mobile

FAQs about unlocking your Sprint device

Unlock Your Phone for Spectrum Mobile

If you're absolutely sure that your carrier unlocked your device (only that carrier can do that, if you're eligible), and if you already tried (to no avail) all the steps provided in this support article:--> How to unlock your iPhone for use with a different carrier , please contact Apple Support directly, using this link:--> Contact Apple for support and service

Regards

Giulio

There are reasons why a carrier might refuse to unlock a phone.

The obvious one is if the phone was bought on time, or gotten for "free", with the cost of the phone folded into the monthly cost of the cellular plan. Cell phone companies aren't in the business of giving phones away – so they're not likely to unlock a phone if the original contract term is not up yet.

A less forgivable one is if you completed the contract term, but they figure that as long as they have you locked in to their business, they might as well keep you locked in.

Either way, if they intend on keeping the phone locked, they should tell you that, rather than telling you that the phone is unlocked.

Then your carrier lied to you.

In the past it was necessary to restore the phone to factory settings (then restore a backup) using a computer to complete the unlock, but that should no longer be necessary. It can’t hurt, however.

That means your carrier did not unlock it, no matter what they told you.

Who is your carrier?

Recently, I asked AT&T to unlock a phone here and the phone display indicated that the phone was unlocked within seconds. No restore to factory settings, or even a simple restart was required.