render() :
React.js library has two components:
1. Class components
2. Functional Components
- Class components uses render function.
The ReactDOM.render() function takes two arguments, HTML code and an HTML element.
React renders HTML to the web page by using a function called render().

purpose of render() : The purpose of the function is to display the specified HTML code inside the specified HTML element.
In the render() method, we can read props and state and return our JSX code to the root component of our app.
In the render() method, we cannot change the state, and we cannot cause side effects( such as making an HTTP request to the webserver).