I need to unlock the operator's iPhone

See this Apple article: How to unlock your iPhone for use with a different carrier

How to unlock your iPhone for use with a different carrier - Apple Support

Apple can't unlock your iPhone for use with a different carrier. Only your carrier can unlock your iPhone.

You need to contact your Carrier.

Or do you need the PUK code?, See this Apple article: Use a SIM PIN for your iPhone or iPad

Use a SIM PIN for your iPhone or iPad - Apple Support

If it is locked to Cricket, only Cricket can unlock it. You will have to meet their requirements in order for them to do so.

You can find their unlocking policy here: https://www.cricketwireless.com/legal-info/device-unlock-policy.html

You can't. Cricket doesn't offer unlocking.

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