Educated is a memoir, a type of autobiography. A memoir, whose name comes from the French word for "memory," focuses on the author's recollection, rather than the research-heavy mode of a standard autobiography. A memoir also usually focuses on a particular period, unlike a biography, which will usually cover someone's whole life. Memoirs also usually display an overarching theme or conflict that needs to be resolved, like Tara's attempt to reconcile her drive for education with her relationship with her family.
The book also contains some features of a novel, with its short chapters framed around dramatic plot events, intentional character arcs, and figurative language. Thus Educated also takes inspiration from the genre of the bildungsroman, or coming-of-age novel, which recounts a young character's process of learning, maturing, and changing into adulthood. Many such novels center around education and how it can free someone from an oppressive situation. In this way Educated bears many similarities to Jane Eyre. This 1847 novel by Charlotte Brontë features the title character narrating, in the first person, her emotional and spiritual development through her own education as a path to liberation.
Notably, though, Westover intentionally does not intend her book to be a satire or critique of Mormonism in general. She specifically emphasizes in the Author's Note that this is a story of her family in particular, not a commentary on all Mormons. Educated is a personal story of Westover's life, told so as to resemble a bildungsroman.