The PMI process to manage communications is in the communications management knowledge area and the executing process group. Communications are key to keeping the stakeholders informed. This process covers creating, distributing, recording the messages and other techniques used to communicate.
According to the PMBOK, this activity has the following characteristics:
Manage communications is described in section 10.2 of the PMBOK.
According to Harold Kerzner (Project Management: A Systems Approach to Planning, Scheduling, and Controlling, 11th Edition, p 269), "In a project environment, a project manager may very well spend 90 percent or more of his or her time communicating."