What does Delegating mean in GTD?
It means handing off the execution of an action or task to someone else when you are not the best person to do it. This can be for various reasons: lack of skills, lack of time, lack of necessary resources, financial issues, etc.
When you delegate an action, you are still accountable for the result and, therefore, you need to keep track of it in order to review the process. To do this, you will need to put reminders of the delegated tasks in the Waiting For List.