How do you address wedding invitations to a family with different last names?

When a family has different last names, the outer envelope should list each adult separately, with their own title and full name. For example, write Ms Sarah Jones on the first line and Mr Tom Brown on the second line. This is correct whether they are married, partners, or co-parents. On the inner envelope, you can be more relaxed. You might write Sarah and Tom, or if they have children, Sarah, Tom and the children's first names. If they share a surname but have different titles, use both titles with the shared surname, such as Dr and Mrs Smith. If you are not sure of a person's title, it is acceptable to use their full name without a title. The key is to be respectful and clear. Always double-check the spelling of each name and use the form of address that each person prefers. If you are inviting a family where the children have a different surname from one parent, you can list the children's first names on the inner envelope without a surname, which avoids any confusion.