Closing the Letter. Choose a Closing: One must use a proper closing in a business letter. Use a comma (,) after it. Sign the Letter: Always sign the letter in ink. If sending a printed copy, always affix the scanned signature. Make Note of Enclosure: One must properly enclose a list of attached documents with the letter. One can use the abbreviation of the enclosure, i.e., Encl. or Enc.
When your letter is to more than one person, write out all of their names separately, separating them with commas. For example, "Dear Mr. Hobbes, Ms. Luxe, and Mr. Hopman." For married couples, if one person in the couple has changed his or her name, you only need to use the last name once. For instance, "Dear Mr. and Mrs. Smith."