General practice when writing a business letter is to use a Times New Roman size 12 font, with a left-justified block format that is single-spaced within paragraphs and double-spaced between paragraphs. To write the letter, include the sender's address, date, inside address, salutation, body text, closing and enclosures. Use a professional tone, be concise and state your point early in the letter to avoid miscommunication.
First, type the sender's address. Typically, the sender's address is included in the letterhead. If you do not use a letterhead, type the sender's address at the top of the letter one line above the date. Include only the address because the sender's name is included in the letter closing. Next, type the date using the "month, day, year" format. Next, include the inside address or recipient's address. If possible, write to a specific individual within the organization, and include a personal title such as "Mr." or "Ms." Next, type the salutation. Use a colon at the end of the name.
In the body text, state why you are writing. Establish any connection or mutual relationship up front. For business letters that feature a complaint, outline your proposed solution. Always provide proof for claims by using examples or expert opinions. In the closing, state what the reader must do and what you can do to follow up. If you enclose any supporting documents along with the letter, indicate this by typing "Enclosures" one line below the closing.