Is the invited child coming, will an adult stay, and who is collecting them? A birthday RSVP can involve more than a single tick. Use fragab to collect the practical replies within the invited parents’ group and keep the key times together.
Give the date, start and finish times and meeting point. If the children are going somewhere together, explain where parents should drop them off and collect them. Say early and kindly whether siblings or accompanying adults are included.
If the day is still undecided, first offer a few possible times. Once the date is fixed, collect attendance replies separately. For venue and party ideas, see planning a birthday.
A yes to attending does not automatically confirm transport or an accompanying adult. Discuss contact details and personal needs directly with the parents concerned, rather than in visible comments.
Five people have answered yes in this simple invitation. These are prepared sample entries. Try changing the selection; your changes are not saved. Create your own invitation to collect replies for your party.

For food and supervision, you need the number of children and adults, not just the number of list entries. Follow up with anyone who has not replied. Confirm changes to pickup or particular needs with the parents involved.
A separate potluck list can help if adults are bringing food. Keep the children’s attendance in the original RSVP.