Tracking stolen iPhone 11 with IMEI and serial number

Here is what to do: If your iPhone or iPad was stolen - Apple Support

Serial numbers and IMEI numbers cannot be used to track devices, other than by police and carriers.

There’s no other way to track it if it’s been turned off. You can try to keep an eye on the location to see if it comes back online. But the IMEI and Serial Number won’t be able to be used to track the iPhone, those are for identification purposes.

If you had Find My enabled on the iPhone, the phone will still send out a very brief intermittent Bluetooth signal even if the phone has been turned off.

Another Apple device in very close proximity can pick up the Bluetooth signal and forward it to the Internet, so that Find My on another device will display the current location of your iPhone.

This of course assumes that the battery has not run down on the iPhone.

Unfortunately, iPhone thieves know all about this capability on the iPhone, so they often wrap the phone in aluminum foil or place it in a small Faraday bag that will not allow the iPhone to either send or receive a signal.

Stolen phones are almost never recovered, so if your phone has not appeared in Find My after a few days, it probably never will.