How can fix my imei

What do you mean by "fix my imei"?

What's the problem?

If the device is carrier locked, contact the carrier it is locked to. They are the only ones who can unlock it.

If it's been blacklisted, you're out of luck. That's done by the carriers when a device is reported lost or stolen.

Hello,

See this:

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

Good luck.