Our orders are delivered strictly on time without delay 
The elements of Use Case diagram include actors, use cases, subject boundaries, and a set of relationships among actors which may include extends and generalization.
You were hired by Hilltop Motors as a consultant to help the company plan a new information system. Hilltop is an old-line dealership, and the prior owner was slow to change. A new management team has taken over, and they are eager to develop a first-class system. Right now, you are reviewing the service department, which is going through a major expansion. You decide to create a model of the service department in the form of a use case diagram. The main actors in the service operation are customers; service writers, who prepare work orders and invoices; and mechanics, who perform the work. You are meeting with the management team tomorrow morning. Create a draft of the diagram to present to them by developing a Use Case Diagram and Use Case Description.
