In the scrum model, Epic defines a high-level expectation of a feature or software. For example, when you want to build software that keeps a track of your sales, an Epic can be “As a business owner, I want to build a software which I can use to keep the record of my sales”. Now is the great Epic which tells about the purpose of software that needs to be built. More Epics can be derived from this great Epic which can further tell about the different modules of the application. Let’s take another example that is derived from this great Epic and talk about the further modules of this software application.
Example: As a business owner, I want to see all the financial reports of my sales on a single dashboard.
Now, this Epic further talks about a specific module of the application, but still at a very high level. The Epic is further broken down into user stories which give more granular information about the Epic and hence a product backlog is created.