Use Case
You might say
Write the refund request end to end: how the customer starts, how the system responds, and what failure looks like.
A description of the main interaction and important exceptions between an actor and a system while reaching a goalFor an order refund, a use case states eligibility, what the customer submits, how the system responds, and how expired or duplicate requests end. It describes observable behavior without prescribing internal code.
Also calledSystem Use Case
Further reading