The Figure below shows, what a use-case might look like UML schematic form. The usecase itself looks like an oval. The actors are drawn as little stick figures. The actors are connected to the use-case with lines.
Use-case 1 − Sales Clerk checks out an item
● Customer sets item on counter.
● «uses» Swipe UPC Reader.
● System looks up UPC code in database procuring item description and price
● System emits audible beep.
● System announces item description and price over voice output.
● System adds price and item type to current invoice.
● System adds price to correct tax subtotal
So, the «uses» relationship is very much like a function call or a subroutine.
The use-case being used in this fashion is called an abstract use-case because it cannot exist on its own but must be used by other uses cases.