Your guests will not only be able to RSVP to your custom invitation, but can contribute to a shared album during and after your gathering. You can even allow them to contribute to a shared Apple Music ...

You can even allow them to contribute to a shared Apple Music playlist for your party ... Tips for Using Apple's Party Invitation App ...

This new app, available for download from the App Store or on iCloud.com, allows users to easily send invitations, manage RSVPs, create collaborative event albums, and curate Apple Music playlists.