client/src/index.js

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';

import Header from "./Components/Header";
import 'bootstrap/dist/css/bootstrap.min.css';

ReactDOM.render(
  <React.StrictMode>
    <Header />
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);