Unlock sim card

ONLY the carrier the phone is locked to can unlock it. Apple has nothing to do with carrier locks. We can't help you remove a carrier lock. You need to contact the carrier the phone is locked to and see IF the phone qualifies to be unlocked and what, if any fees may be required to be paid to unlock it.

See this from Apple --> How to unlock your iPhone for use with a different carrier - Apple Support

Right at the top you'll see Apple say they cannot unlock a carrier locked iPhone.

You can find your PUK by logging in to your carrier’s customer portal, or calling their tech support. If you have used up your 3 tries your SIM has been deactivated, and you will have to contact your carrier for a new SIM.

loni296 wrote:

I want to unlock my sim card but the PUK code is forgot

Lawrence Finch gave you the right advice, which is to contact your carrier for help.