In your file index.js, change to:
import React from "react";
import ReactDOM from "react-dom/client";
import "./index.css";
import App from "./App";
import reportWebVitals from "./reportWebVitals";
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
<React.StrictMode>
<App />
</React.StrictMode>
);
reportWebVitals();
For Typescript
Credit from comment section below answer: Kibonge Murphy
import React from "react";
import ReactDOM from "react-dom/client";
import "./index.css";
import App from "./App";
import reportWebVitals from "./reportWebVitals";
const root = ReactDOM.createRoot(document.getElementById("root") as HTMLElement);
root.render(
<React.StrictMode>
<App />
</React.StrictMode>
);
reportWebVitals();