Word, Notion, and dedicated novel writing software each work for fiction, but they trade off differently between flexibility and structure.
A word processor like Word is excellent for the actual prose and formatting, but has no built-in concept of characters, worldbuilding, or plot structure — those live in separate documents, if they exist at all.
Notion can be configured into a capable story bible with databases for characters and locations, but building and maintaining that system is manual work on top of the writing itself.
Tools like Author Notebook come with chapters, characters, worldbuilding, and story structure already modeled for fiction, trading some of Notion's flexibility for less setup and maintenance overhead.
If you mainly need clean manuscript formatting, a word processor may be enough. If you want a fully custom system and do not mind building it, Notion is flexible. If you want fiction-specific structure without building it yourself, dedicated software is worth trying.
A practical approach to character profiles, relationships, and a cast list that stays readable.
Locations, factions, rules, and timeline consistency, covered step by step.
A practical, act-based approach to planning your novel before you draft.