This system UML use case diagram depicts the behavior of a system and aids in the capture of the system's requirements. Use-case diagrams describe a system's high-level functions and scope. These diagrams also show how the system and its actors interact with one another. In use-case diagrams, the use cases and actors describe what the system does and how the actors interact with it, but not how the procedure operates internally. Use-case diagrams depict and define the context and requirements of an entire system or key components of a system. You can model the complex system with a single use-case diagram or many use-case diagrams to model the system's components. You would typically create use-case diagrams in the early stages of a project. Go ahead and start using EdrawMax to create beautiful use case diagrams for your organization.