My iPhone was stolen and erase how to block

Read this support article, which presumes you DID have Find My enabled before the phone was stolen --> If your iPhone or iPad is lost or stolen - Apple Support

If Find My was NOT enabled prior to the phone being lost, all you can do is look for it with your eyes. And if the phone is offline or not connected to a network, even with Find My turned on, it can't be tracked.

Also be prepared for scam messages, which appear to be from Apple saying your phone has been found and to prove it is your phone, you need to enter your sign in credentials. Apple NEVER gets involved in lost or stolen phones and does NOT send such messages. Providing the information, will release the phone so the thieves can erase and use it or sell it. They sometimes even threaten you. Don't fall for it.

Finally, call you carrier and ask them to Blacklist the phone so it can't be activated on any network again.

Also, DO NOT remove the phone from your account. If you do, you'll release the phone to whoever has it to erase it.