Yes. We are able to add a link to an RSVP service of your choosing. Motion Stamp does not create RSVP forms. However when you order a webspage we can create a button which will take your guests directly to an RSVP that you suppply us. If you are looking for an RSVP option, there are quite a few out there.
Google forms is a great way to Rsvp and it's free. You can see an example of a Wedding RSVP here. RSVP Example Motion Stamp provides you with a free Google forms rsvp template, that matches your chosen invitations. You can ammend it and make your own.
We have a handy blog which explains how to create your own free Google RSVP. Which can be viewed here. https://motionstamp.com/blogs/news/evite-rsvp
Otherwise, if you haven't already found them, websites such as 'With Joy', 'Rsvpify', or 'Say I do' all have very comprehensive RSVP tools and databses for hosts.
All allow you to create a RSVP page, which we can link to. If you want to take it a step further they also allow you to create a full website, which allows you to place your Motion Stamp invitation video within them.