A formal letter for a membership typically follows a professional format and includes specific information related to the membership application or request. "Attn:" is used when you address a letter to a company, but want it to be directed (if possible) to a specific person at that company.The Attention field is used to give a brief description of the address itself. Download a proof of residency letter template for family members, notarized or non-notarized, tailored for legal use. An attention letter is a type of business letter with an attention line. In simple terms, you add an extra line to your letter stating who the letter is for. You can use "Dear" as your greeting, and proceed to address all the recipients. In a business letter, you end the salutation with a colon rather than a comma. I am a first-year law student at Harvard Law School and am writing to apply for a volunteer summer internship at your office. For example, an executive summary will be a full page of your proposal, but in a LOI it will only be one paragraph.