When React 16.8 was released officially in early February 2019, it shipped with an additional API that lets you use state and other features in React without writing a class. This additional API is called Hooks and they’re becoming popular in the React ecosystem, from open-sourced projects to being used in production applications. React Hooks are completely opt-in which means that rewriting existing code is unecessary, they do not contain any breaking changes, and they’re available for use with the release of React 16.

https://www.smashingmagazine.com/2020/04/react-hooks-api-guide/