If I asked you why Langston Hughes wrote the short story "Thank you M'am," what would you guess? Your question deals with the purpose of texts and the reasons that writers create those texts. When you read the short story, did you pick up a lot of facts, statistics, or other information? Do you think that was Hughes's goal was to provide readers with information?
While it is true that readers can pick up information (like a moral lesson in the case of "Thank You, M'am"), the primary purpose of stories is to entertain readers with a plot. We follow along with a sequence of events in order to find out what happens, and then we think about the significance of those events. So, we can definitely learn a lot from a short story (from thinking about them and discussing them and how they related to our lives and the world), but we don't usually read them to pick out specific facts and information.
By contrast, the purpose of an informational text is to provide specific information. A news article, for example, answers the journalistic questions of Who, What, Why, Where, and When (and sometimes How), so there might be the elements of a story, but the article is not primarily meant to entertain us (like a short story), but instead to give us "just the facts" (as a TV detective used to say).
So, there are two clear and simple differences between "Thank You M'am" and an informational piece. The first is purpose: "Thank You M'am" is written to entertain and provide a lesson through plot while the informational piece is written to provide specific information to readers. The second difference is in organization: the short story is arranged as a narrative plot (a sequence of events), and the informational piece is organized by what the reader needs to know first, second, third, etc. in order to understand the information. Examples of informational passages include news articles, encyclopedia entries, and informational websites.