How do I lock my stolen iPhone?

If your iPhone or iPad was stolen - Apple Support

Your phone is locked with the Passcode if you used one, which everyone should do anyway. No one will be able to get into the phone by guessing, as it would be locked automatically after too many failed attempts.

You can mark it as lost and track the device using Find My, but the IMEI number will be no help at all. And again, you would need to have Find My turned on, which everyone should.

You should contact your cell provider to report the lost device to them and more information is available to you here:

If your iPhone or iPad was stolen - Apple Support

Please do not repeat posts.

Only your carrier can track your iPhone with the IMEI number, and they will only do so with a court order or when someone’s life is imminent danger. The only way you can track your iPhone is with Find My.

I would advise you to turn on Lost Mode, report it to your carrier and local law enforcement. If your iPhone shows up, do not follow it, that can put your safety at risk.

You may get some messages claiming to be from Apple or Apple Support stating your iPhone has been found, but do not interact with those. That is the thief which is trying to get you to remove Activation Lock on your iPhone, making the device fully usable to them.

Please also review the following article ⇢

If your iPhone or iPad was stolen - Apple Support