Use cases are typically written by business analysts and can be employed during several stages of software development, such as planning system requirements, validating design, testing software and creating an outline for online help and user manuals. A use case document can help the development team identify and understand where errors may occur during a transaction so they can resolve them.

Every use case contains three essential elements:

• Contact Profiles — this can be a single person or a group of people interacting with the process.
• Objectives. The final successful outcome that completes the process.
• Platforms. The process and steps taken to reach the end goal, including the necessary functional requirements and their anticipated behaviors.

Characteristics 

Use cases describe the functional requirements of a system from the end user’s perspective, creating a goal-focused sequence of events that is easy for users and developers to follow. A complete use case will include one main or basic flow and various alternate flows. The alternate flow, also known as an extending use case, describes normal variations to the basic flow as well as unusual situations.