Where do you put "and guest" on the invite?

I just wrote ours on the envelope! Unless you have rsvp cards that say " ___ seats reserved" then if you put 2 they most likely would assume they have a plus one

Yes - on the envelope!! If you are doing inner and outer envelopes you would write "Mr. John Smith and Guest" on the inner envelope and just address the outer to "Mr. John Smith", but if you're just doing outer envelopes put it right on the envelope!

I put it on the inner envelope. So outer was addressed to Ms. Jane Smith, inner said Jane and guest.

I put it on the envelope. You can also put it on the inner envelope if you're using one.

I did what Mrs. Fall Bride suggested, as well as the " ___ seats reserved in your honor" on the RSVP card.

Are these true +1 (single people getting guests) or are these couples who aren't married? 30% of your list sounds like a lot of truly single guests. Even if you don't know the BF/GF, if they're couples, you should address the envelope to both people by name.

We only had two true +1 situations on our list, so I wrote a small note on nice cardstock saying they were welcome to bring a guest and asking they provide a name on the RSVP card.

Thank you everyone for your help! @MrsKi(tobe) you're right, I guess we only have like 6 truly single people. Really appreciate all the advice!!