Components are the primary building blocks of any React application. A component is a self-contained, reusable piece of code that defines how a part of your user interface should appear and behave.
The simplest and most modern way to define a component in React is to write a standard JavaScript function.
function Welcome() { return <h1>Hello, Welcome to React!</h1>; }
These are known as Function Components because they are literally just JavaScript functions. They can accept inputs (called "props") and return React elements detailing what should appear on the screen.