Used primarily with formal invitations, the ungummed inner envelope is simply addressed "Mr. and Mrs. Johnson" (first names omitted, no address).
All family members should be included, however it is best not to use the words "and family." Instead, list all guests' names, keeping in mind that names of children may be spelled out (for example: "Molly and Tristan") and written below the parents' names in order of age.
Feel free to address close relatives informally, i.e. "Aunt Alice."
If you are including an invitation for an escort whose name you do not know, you will need to ask for the escort's name. It is preferable to send the escort a separate invitation.
Middle names may be eliminated or written in full.
After the inner envelope is addressed, it is inserted along with all accompanying enclosure items into the outer envelope.