I found this list of tips for addressing invitations in the Elegala website wedding invitations guide:
- No abbreviations, except for Mr., Mrs., Ms., and Jr. States must also be spelled out.
- If one of your single guests is bringing a date that you know personally, send that person a separate invitation instead of including "& Guest" on the inner envelope.
- If you are unable to obtain the name of a single friend's guest - indicate on the inner envelope that they may bring a guest - NOT on the outer envelope. (this looks awkward)
- Unmarried couples who live together should receive one invitation, where their names are listed in alphabetical order and on their own lines.
- Invited guests who are living together as roommates, not couples, should each receive their own invitation.
- List the names of children under the age of 18 who still live at home on the inner envelope instead of "& Family" which can be very ambiguous and easily misinterpreted. Children over the age of 18 should receive their own invitation, regardless of their living situation.
- The traditional, married couple recipient should follow this format:
- Mr. & Mrs. Ryan Parker 2211 First Street, Apartment 3 San Diego, California 92109