In UML sequence diagrams, you can show the operation signatures
or message signatures of individual messages to visually represent the communication
in interactions.
You must have a sequence diagram open that contains messages.
To show an operation or message signature in a sequence diagram,
in the diagram editor, right-click a message; then click .
The operation or message signature is displayed in the name compartment.
Nota: If the message has no arguments, the operation
signature of the message is displayed.