You can address it:
John Doe and Jane Smith
Street Address
City, State, zip code
The correct way to address an envelope to a married couple that have different last names is to use both of their names. For example, you could write Mr. Johnson and Miss or Ms. Dwyer.
Dear Mr. (name) and Mrs (name)
The correct way to address the envelope is: Mr. John Doe & Dr. Jane Doe.
You may say to Signore & Signora or abbreviate it as Sr. & Sra.
You can address it to only one, or address it to both using both names. Either way is acceptable.
"Mr. & Mrs. C. Smith" if you know his first initial. If not, then "Mr. & Mrs. Smith" would be correct.
* Senor & Senora ____________________. Senorita is single, Senora is married.
The envelope should read: Mr. John Doe & Dr. Jane Doe. If you don't know her first name then put: Mr. & Dr. John Doe.
With their names and the address. Ms. Jane Hope and Ms. Marie Faith OR Jane Hope and Marie Faith
One can purchase an envelope printer in many different stores. Best Buy and Radio Shack often times have a couple different envelope printers available to purchase.
If you are not sure they are separated or divorced then address your envelope to both of the. If you know for sure they are separated then send a separate envelope to each one.
When you want to address an envelope using both Christian names of the couple you would write it as: Mr. John Doe & Mrs. Jane Doe (example.)