Addressing Inner & Outer Envelopes?

Okay, on the outer envelope do you put & Guest? or do you just put Ms. Jane Doe? and on the inner envelope put, Jane & Guest?

In the address, do you spell out the numbers?

Ms. Jane Doe & Guest
One Mississippi Boulevard

????????????????????????

Thanks!

Ms. Jane Doe on outer, Ms. Jane Doe and Guest on inner.

Depending on your formality, you write out the numbers or not. Formal, yes. Semi-formal or informal, no.

Thanks! Do you write out the word and?

Can I send one invite per hosehold, or do I have to send seperate invites to my cousins, if I am inviting each of them with a guest?

For example, I have a single aunt with 3 daughters that live in the house. Two of the daughters have boyfriends one doesn't. What do I do, how do I address this issue?s

Well, formally, you send an invite to everyone over 18, regardless of where they live. But I don't think you have to.

You could address them like this:

Mrs. Aunt Lastname
Ms. Cousin 1 Lastname
Ms. Cousin 2 Lastname
Ms. Cousin 3 Lastname
Address

Or
(if they have the same last name)
Mrs. Aunt lastname
Ms. Cousin 1, Ms. Cousin 2, Ms. Cousin 3 Lastname

The inner envelope would read

Aunt first name, Cousin 1 and Boyfriend, Cousin 2 and boyfriend, and Cousin 3

It's best if you get the boyfriend's names.

but if cousin 3 is over 18, she should still be & guest on the inner envelope, since you are inviting the other cousins' boyfriends.