Web apps (applications) and websites are in essence the same thing. They run on a web server somewhere, whether it’s on-site physical infrastructure or in the cloud, and tend to have a database serving the data behind the scenes.
The distinction is made when it comes to their use. Below is a description of the general differences between “Web Apps” and “Websites” but sometimes they overlap and incorporate features of both.
Generally speaking, a web app offers user login and deeper functionality, whereas a website offers a landing page for a customers (after they have found them on a search engine) and contains contact details, product details etc.
Web apps are places on the internet where customers/users return regularly to do a specific set of actions, websites are more often “discovered” and browsed by unfamiliar users.