The doorstep farmer use case is a written description of how farmers will perform tasks. The diagram below shows that the doorstep farmer use case outlines a system's behavior as it responds to any request. As the use case diagram illustrates, each use case is represented as a sequence of simple steps, starting with the doorstep farmer's goal and ending when that particular goal is fulfilled. In simpler words, a use case is an abstraction that describes all possible scenarios involving the described functionality. Lastly, such use case diagrams are pretty important in creating UML diagrams. Use case diagrams to capture the system's functionality and requirements in UML diagrams. It captures the dynamic behavior of a live system. A use case diagram consists of a use case and an actor.