If you double-click on a requirement in a diagram or right-click on a requirement in the Project Browser window and select Properties, you can edit the main properties for the relevant element. Requirement properties are a little different to normal properties; they are mainly focused on the status of the requirement, who owns it and when it was created and/or updated.
Enter a short description to describe the requirement in a sentence, then enter the full requirement details in the Details panel at the bottom of the dialog. Set the status, difficulty, priority and other parameters as required.
When you have completed filling in details for the requirement, click on the OK button.