Whether you write a formal business letter or a quick memo, the way you format and write these communications says something about your professionalism. Once you master each style, you can write to associates, customers and vendors in a way that communicates clearly while maintaining a reputation for professional writing.

Business Letter Formatting and Tone

Business letters begin with headings containing your company name, address and the date. The recipient's address comes next, then the salutation. The body contains three to five paragraphs, followed by a close such as "Sincerely." You then sign your name and type it below the signature. These elements are placed flush left in block style, with no indentations. A modified block style allows for indented paragraphs with everything else flush left. This presentation works for very professional business communications that have a serious tone.

Memo Appearance and Voice

Memos use informal approaches. A memo has three lines: "To" "From" and "Re." The topic of the memo is written in "Re." The body format looks like that of a letter. You don't need to sign a memo, though, and the tone can be conversational, without including colloquialisms. This works for internal communications to recipients who work for your company and are familiar with the topic.