React function components are like Javascript functions that can receive props and return react elements. They can not have state hence called stateless components.

A class component is a Javascript class which extends React.Component class. Class component defines methods that get executed during the lifecyle of that component.

Components can be difficult to understand if you are new to ReactJS. In short, they are the core building blocks of an application. A react component is an independent and reusable piece of code.