response envelopes???

what goes ON the response envelope? how should it be worded? like should it say:

Mary Smith
123 Lane
Blah Blah, USA 12345

OR


Ms. Mary Smith
123 Lane
Blah Blah, USA 12345

OR

Ms. Mary Smith and Mr. John Doe
123 Lane
Blah Blah, USA 12345

HELP!!!

mine says

Miss. Mary Smith