Hi Kathy,
Thanks for reaching out and for your interest in our products!
This functionality is not part of our plugin -yet- but there’s a handy plugin called Event Rocket that provides some extra functionality to our Events Calendar. Among other things it enables a simple RSVP system.
This feature is on our product roadmap and it’s planned to be out before the end of the year – so hopefully we will have that functionality integrated in our own plugin 🙂
Please let me know if there’s anything else I can help you with,
Best,
Nico