What is a User Story?
As a {user}
I Want {desirable feature}
So that {a reason}
User Story represents the conversation with a user for the desired feature or capability which will provide the value to the user post-implementation. User Stories shift focus from writing about the what is required to discussing on what is required.
A good user story or in fact a well-formed user story will follow the INVEST criteria.
Independent: We want to be able to develop in any sequence.
Negotiable: Avoid too much detail; keep them flexible so the team can adjust how much of the story to implement.
Valuable: Users or customers get some value from the story.
Estimatable: The team must be able to use them for planning.
Small: Large stories are harder to estimate and plan. By the time of iteration planning, the story should be able to be
designed, coded, and tested within the iteration.
Testable: Document acceptance criteria, or the definition of done for the story, which leads to test cases.