Are you looking to customize the RSVP headers to your invitation?
Please follow these steps to customize your RSVP headers while creating your event:
Click Guest Options while on the Preview Invitation page (Step 4 of 6).
Click on the dropdown to view the RSVP style options.
Select the format you wish to use.
Note: The custom reply headers will show for your guests on the guest list AFTER you send your invitation.