In case of an emergency, most responders know to check the carseat for any identification. You'd ideally laminate this tag or cover in contact paper, punch a hole and tie it to the inside of the carseat. Put a tag in EVERY seat your child has-- grandma's car, etc.
You can also use this eon the baby bag, or anywhere else you might need it in case of emergency.
Download once, print often to update!