Desmond Tutu was a Bishop, so the correct salutation would be, "Your Excellency".
the correct salutation for two men is Messrs
"Dr and Mrs Smith" is the correct salutation. (With Smith replaced with the correct surname)
After the salutation of a business letter, the correct punctuation to use is a colon.
Dear ms
Mrs. or Ms.
madame mayor
His Excellency, Ambassador of ................... This salutation can be used when writing to the Forein ambassadors of all countries.
chief counsel
Honorable Consulate
Consul of China
Dear Sirs and Madam: