I have a stray dog how do I get rid of it

At the very least, take it to a no kill shelter

First thing you need to do is take it to a vet to see if it's chipped, place found ads in the paper, at all the shelters and on apps like NextDoor which are very good at helping find dog owners. As a last resort you try to re-home it or turn it in to a shelter.

How long have you had it