Question on Invite Assembly

I know this has probably been asked before...

I have never recevied an invitiaton where the inside envelope (that has the invitiation, etc in it) was printed on. AM I supposed to be writing on these envelopes? I mean, if someone is being invited with a guest, would I write on that?

I'm just assembling my invitations and getting them ready to go out in the mail. From what I understand and what I'm going to do, yes you put the names on the inside envelope, like Mr. And Mrs. Smith, Mr. Smith and guest, or depending on how formal your wedding is you can just do Danny & guest. Hope this helps.