Here's why:
* "Inform" is the root word, meaning "to give knowledge or news."
* "-ation" is a suffix, but it's not attached to "inform" in this case.
The word "information" is formed by combining two separate words: "in-" (meaning "in" or "into") and "form" (meaning "shape" or "structure").
So, "information" means "to put something into shape" or "to give shape to something," which relates to the act of giving knowledge or news.