The adjective informational describes anything that provides facts or knowledge. The informational booklet that came with your new microwave will tell you how to use it.
You might prefer frothy romance novels while your sister enjoys informational nonfiction and scholarly articles. Informational writing does just what it sounds like, giving plenty of information about a particular topic. Your science class most likely requires informational textbooks and informational lectures. This word comes from inform and its Latin root, informare, "to shape or educate."