The city requires every cat to be microchipped and wear collars (whether indoor or outdoor). shelter people gave me a collar with metal ID tag, but my kitten hates it and fights with it constantly.
Try putting it on for a few minutes at a time, and offer yummy treats when it goes on. Gradually extend the time until he fully accepts it. You could also try a collar in a different material or design, just in case there's something about that particular design that bothers him.