For this discussion, you need to research the best practices for two specific genres of business writing. I would recommend using "best practices ________" as your search terms. While these won’t always be academic sources, they will serve to begin our discussion of the conventions of each genre.
For your 200-word original post, you should let us know what genres you researched, tell us what those best practices are, and then discuss anything you found surprising about the best practices for specific documents.