Which formatting style includes keying in all lines at the left margin?

Block-style letters feature a formatting approach where all text is aligned evenly at the left margin, including the date, address, salutation, body, and closing. This uniform alignment creates a clean and organized look that is widely used in business correspondence due to its straightforward style and ease of reading.

In contrast, other styles such as the indented style involve paragraphs being indented at the beginning, leading to a variation in left margin alignment. The modified block-style letter contains elements that are left-aligned as well as some that are indented, usually the date and closing, which can cause inconsistencies in margin appearance. Meanwhile, the hanging indent letter specifically applies indentation to the second and subsequent lines of each paragraph, rather than aligning all text to the left. Therefore, the distinctive characteristic of block-style letters is the complete left alignment, making it the clear choice in this scenario.