This process is the engine for driving the first stage of the project, the initiation stage (for project planning).
The work involved in this process includes the production of the project plans (in a broad sense) which will together form the Project Initiation Document (PID). The PID includes such items like the Quality Management Strategy, Risk Register and anything else that defines what the project is about and how it will be controlled.
For more information about the Project Initiation Document, click here