How do I get my IMEI number from a stolen IPhone

The above is correct.

For the Apple info:

Find the serial number or IMEI on your iPhone, iPad, or iPod touch - Apple Support

...and scroll down to the section

If you don't have your device

...

Just contact your carrier that was used on that iPhone and they will have the IMEI number in their history. Personally, the police would want the Serial Number instead of the IMEI number. If you need the serial number then you can obtain that by logging into your Apple ID and checking the device list and clicking on the item in question.

Axel F.