Dr. and Mrs. or Dr. and Mr.
Dr.- If male. Dr.(Mrs.)- If married female. Dr.- If unwed female. Dr. and Dr.(Mrs.)- If the couple are both physicians.
What kind of couple? Unmarried? Their names, So and so, and so and so. Married, Mr. & Mrs., any way you want to write it. Or, Mr. and Ms.
Mrs, Mrs & Mrs
The proper salutation for a female can vary depending on their marital status. Mrs. is used for women who are married. Miss is used for women who are single, while Ms. is used for women who are both married and single. This salutation is safer to use if one is unsure of the woman's marital status.
"Dr and Mrs Smith" is the correct salutation. (With Smith replaced with the correct surname)
The proper salutation for a man who is a doctor is Dr. David Jones or you can say Mr. David Jones, M.D. either way is ok. If the Doctor is married: Dr. David Jones & Mrs. Jones.
Rabbi and Mrs.
Dear Mrs Ambassador..
Dear Mrs. Obama,
Dr. and Mr. Smith.
probabaly just a mrs. would suffise