They are to plan, organize, lead, and control. The best managers are masters of making things happen. They create far more energy than they consume and, instead of taking energy from an organization, they channel and amplify it back to the organization. Successful managers create compelling visions for their employees to strive for, and then they get out of the way.
Great managers allow their employees to do great work.
They delegate responsibility and the authority necessary to get a job done. This is a vital function of management since even the world's greatest managers can't succeed all by themselves. To achieve their goals, managers depend on the skills that their employees offer them and their organizations. It used to be that the job of managers was to give orders and to make sure that their employees did as they were told. This is no longer the case.