Create an empty GitHub repository which can be public or private.
Create a simple React app
npx create-react-app netlify-react-app cd netlify-react-app
Set Github remote origin URL.
git remote add origin https://github.com/gitname/netlify-react-app.git
Push the code changes to
git add . git commit -m "Configure React app for deployment to Netlify" git push origin master
Go to Netlify and import the project which is the above GitHub repository.
Click on deploy site and wait for a few seconds for the deployment to be completed.
Now you can test the app deployed by hitting the below URL.