How do you identify the use case in UML?

Answer 1

Each use case is some service or unit of functionality provided by system to the external user (actor).

First, define what is the system. For example, system is Bank ATM.

Second, define user of that system. For example, a Customer of that bank.

Now, the use case is some complete service that the user wants from the system.

Examples of use cases for the system and user above would be Check Balances, Withdraw Cash, Deposit Funds,etc.

Answer 2

In UML, you can identify a use case by looking for a specific notation on the diagram. A use case is represented as an ellipse with a name inside it, usually describing a specific function or goal of the system. It should be clear, concise, and focused on the primary actions or interactions that the system needs to perform in response to an actor's request.