If you know exactly who you will be inviting and want to only allow people who are on your guest list, you can enable this feature from your RSVP settings!
To find your RSVP settings, go to RSVP from your dashboard and click on "RSVP Settings".
Turn on the Enable RSVP's.
When this option is turned on, RSVPs will be limited to guests in your guest list manager who have been invited (aka you've sent them a digital or physical invitation) or for anyone who visits your site.
How does an invited guest RSVP?
When someone clicks on the RSVP button on your website, they will be asked to confirm their names.
When the RSVPs are restricted to the guest list, only exact name matches will be able to RSVP on your website.
If you would prefer not to restrict your guest list or don't know the names of all the guests who will be attending your wedding, you can turn this option off.
What about any plus one guests?
In the case of +1's, you can still restrict your guest list as long as the primary guest enters their name to RSVP.
The primary guests will be able to enter the name of their +1 guest and their information will be stored in your guest list manager.