Requirements are implemented by model elements, such as Use Cases, Classes, Interfaces and Components. You can specify this relationship in Enterprise Architect using the Realization link. A model element is marked as 'Realizing' a requirement. Once this link exists, Enterprise Architect displays the requirement in the Require tab of the element Properties dialog, in the Requirements Hierarchy window and in the Dependency and Implementation reports, as well as in the standard RTF output.
A quick method of generating a Realization link is to drag a Requirement element from the Project Browser window over an element in a diagram that is to be the implementing element. Enterprise Architect interprets this as a request to create the Realization link and does so automatically. To confirm this, perform the action and then go to the Require tab of the target element. There should now be an external relationship to the requirement that was dragged over the target.