What language did you use on RSVP card to indicate a plus one was allowed?

A lot of the templates for RSVP cards saying things like: “Accept or Decline? ______ will be attending.” as of leaving it open ended how many people can tag along.

I want an RSVP card that has like a “plus one” check box or something so they know they can bring a plus one but that we would like to know if they would or not? I’m just not sure how to gracefully put that on the invitation and RSVP cards.

Any templates or examples that I can look at?

Thank you!