How do you address an envelope to a married couple both captains in the army?

There are several accepted ways to address such an envelope including the following: Mr. & Mrs. John Doe & Family. Jill and John Doe and Family. Jill Roe and John Doe and Family.

An Frau und Herrn (name) or if they have a child/children An Fam. (name). Fam. stands for family.

I would say The Reverands John and Mary Smith.

Try "Doctors Judy and John Jorgenson" or something like that, where the names are correct. If you aren't using first names, you could try doctor and doctor Jorgenson, although it is a bit more...

Try something like Mr. and Mrs. John Doe or if you know them both very well, John and Jane Doe is acceptable.