Copy of Employee ID or employer's letter required. Write check to "Miami-Dade County".State the purpose of the letter in the opening sentence and if you are referring to a bill, include the bill number, author and topic. 29 Unique Letter Greetings to Make a Lasting Impression. Greetings! A "thank you for joining" membership letter should include a personalized greeting to the new member. Use the member's first name in your salutation. This online tutorial is designed to help Miami-Dade County employees, who are seeking advancement, refresh and revise their resumes. A completed MDC international application for admission. Trying to write a membership renewal letter but don't know where to start? Examples of letters addressed to multiple people.