In a use case diagram, the communicates relationship defines how an actor participates in a use case. You can add an arrow to the relationship to indicate the direction the information flows.
Learn why a Communicates shape has red error marking
Right-click the shape, and then click Display Semantic Errors. Read the error message selected in the Errors tab of the Output window.
Name a communicates relationship and add other property values
Open the element's UML Properties dialog box by double-clicking the icon that represents the element in the tree view or the shape that represents the element in a diagram.
Control which property values display on a shape in a diagram by right-clicking the shape, and then clicking Shape Display Options. In the UML Shape Display Options dialog box, select and clear options to display or hide property values.
Control which property values are displayed on the Communicates shape
Right-click the shape, click Shape Display Options, and then select or clear options to show or hide values.
Show end names and other values associated with the end of a communicates relationship
Right-click the Communicates shape, click Shape Display Options, and then select an End option.
Navigate to other views of a communicates relationship
Right-click the shape, click Views, select the view you want, and then click OK.