How do I remove my Apple ID from a stolen iPhone?

why? if you do you will release the iphone so the thiefs or the people the theifs sold it to can use it otherwise they will be locked out by activation lock

if you really wish to let them have the stolen phone so they can use it for anything other than parts then read

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

I agree with the others here. I would add that you should change your Apple ID password as soon as possible.

Ref: Update your Apple ID password - Apple Support

If you do this......you allow whoever has the phone in their possession to take over complete control of the phone.

Are you sure that you want to do this?