If you are confused whether your iPhone is unlocked or not, then don’t worry, you can perform a few very easy ways to check it.
One of the simplest and instant initiated is to insert the card from a different carrier into your iPhone and then turn on your device and see what happened.

If it is connected with the Network and you can make calls or able to use the mobile data, it means that your iPhone is unlocked.
But, if you see a message like SIM Not Supported or No service option, then it usually means that your phone is locked to one carrier and you can follow another way to resolve it.

You must go to the settings directly, and general option, and after that, click on the about option. After that, you must scroll down until you see the carrier lock option from the same screen. If you show No SIM restrictions, it means your phone is unlocked.

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