How To Write A Block Letter . Whenever possible, always include a. Here are a few complaint letter samples to help you understand the format of the complaint letter and help you write a complaint letter on your own. Modified Block Letter format Letter template word, Block style, Block from www.pinterest.com While printing this letter, usage of company letterhead and placement of company logo is a must. In a block style letter, include a space or line between the date and your contact information. The most common layout of a business letter is known as block format.