A letter of resignation should be addressed to the employee's manager or immediate supervisor. At the top of the letter, the employee should indicate the current date of the letter, the manager's name, title, company information and address, followed by a formal salutation, such as "Dear Mr. Smith."
When addressing the manager in the resignation letter, formal titles should be used instead of first names only. The body of the letter should indicate the length of notice provided, the reason for resignation, any plans to transition or train a replacement, and a genuine expression of thanks for the job opportunity.