How do invitation links work with the "invitation required" feature?

We want to do a voting event within our team, for the best picture. We want to authenticate users while having privacy on who voted what.

Does the "invitation required" feature send a unique link to each user, so that each user can only vote once? Or is the invitation general, so that if the user forwards the received email, then other users can participate?

Thank you

Yes, we send an unique invitation link to each invitee. After an invitation is used the link is invalidated an can not be used for a second voting.