A user story in agile project management concisely describes a feature or functionality from an end-user perspective. It typically follows a simple template: "As a [type of user], I want [some goal] so that [some reason]." User stories help agile planning, identify user needs, prioritize work based on value, and deliver incremental improvements. They are lightweight to capture requirements and guide development, focusing on the user's requirements and expectations rather than technical details. Each user story represents a work that can be completed within a single iteration or sprint.