How do I capture the requirements with a story?

A user story (aka "scenario") is a real-life narrative that broadly describes a feature the user wants the system to include, without going into great detail. A user story must include the user who wants the feature, a description of the desired feature, and a clear argument for the business value of the feature.

User stories are leveraged frequently in projects using Agile and other iterative development methodologies. The most common reason for telling a user story is to capture a description of a feature and its business value early in the project, so the feature can be correctly prioritized and sequenced into the project work. A common synonym for "user story" is "requirements card." Although the term "requirements card" more accurately suggests the purpose of a user story, not every feature can be described in a story. "Requirements card" also reinforces the fact that the feature (the star of the user story) is indeed a requirement.