Novels are long fictional characters and events, written in prose, usually in a sequential story. Novels are commonly thought of types of literature, and they are the longest types.
Short stories, like novels, are written in prose. A short story is like a novel but it’s shorter than a novel, it is still understandable, just shorter than a novel.
The last one is a novella, novellas has fewer conflict than a novel, but much more complicated than a short story. A novella is usually longer than a short story, but has a simpler plot line than a novel.