Heroku is the platform as a service (pass). It enables developers to build, run and operate there apps entirely in the cloud.[https://www.heroku.com/]. In other words we can describe as the online server where we can preview our developed app, and show it to concerned users.
Deploying Steps
We will create a simple app that displays helloworld. actually the main idea is to make you familier with steps to deploy project to heroku. I've refered https://blog.heroku.com/deploying-react-with-zero-configuration which provides the comprehensive guide.