User Story: A user story is a simple, concise description of a feature told from the perspective of the person who desires the new capability, usually a user or customer of the system. It follows a specific template: "As a [type of user], I want [some goal] so that [some reason]." User stories focus on the user's needs and the value they derive from a particular feature. They are typically written on index cards or sticky notes and serve as placeholders for discussions between the development team and stakeholders.
Epic Story: An epic is a large user story that cannot be completed in a single iteration or sprint. Epics are too big to fit into a sprint and need to be broken down into smaller, manageable user stories before they can be worked on by the development team. They represent a high-level initiative or feature set and provide a way to organize and prioritize work. Breaking down an epic into smaller user stories allows the team to tackle the work incrementally, making progress towards the overall epic goal in iterative steps.

Epic & User Story