Addressing place cards

I am working on my place cards and I don't know what is the proper way to address a +guest.

Mary Smith and Guest

or

Mary Smith

What about if I know the guest name?

I am so confused. I know some of the names of the + guest but not all.

Am I making any sense! Help please.

I am addressing the cards exactly as they wrote on the response card.

If they wrote guest, I am writing guest.

That is a good idea. I can try that.

I went to the catering hall two days ago and they gave me all this homework to do and I am so confused.

Thx