There are several types of business letter formats that are acceptable and professional. Which you choose should be based on your audience and your personal preference.
Block format is the most common and most widely accepted format used in professional business letters. It is also the format that you will observe in columned newspapers. In the block format all lines of a paragraph are left justified, that is they are all flush with the left margin. The lines included in each paragraph are single-spaced and the lines between paragraphs are double-spaced.
Modified Block Format
With the modified block format the body of the business letter will look exactly like the block format where all paragraphs are left justified with a single-space between paragraph lines and a double space between paragraphs. The only difference is that the date and closing are centered on the page.
Semi block format is typical of that which you would observe in a published novel. This format is the least used for professional business letters. For the indented or semi-block format, the first sentence of each paragraph is indented. The subsequent lines of the paragraph are single-spaced and left justified. There is a double-space between paragraphs.
Many businesses incorporate a mixture of one or more of the standard formats. For example, the sender’s address and date are often right justified in the semi-block format while all other portions of the letter are left justified. If you are responding to a professional business letter, employ the format that the company uses.
Business Letter Writing Tips
Handle yourself professionally at all times. Never use profanity or slang.
Exercise concise, factual, and emotion-free language.
Employ a professional font such as Times Roman Numeral and a legible font such as size 12.
Capitalize in a standard sentence structure format. Using all capital letters insinuates yelling at your recipient, which is emotional and unprofessional.
Use standard white 8- ½” x 11″ paper.