There are three main types of communication: downward, upward, and lateral. Downward communication flows from senior to subordinates and is highly directive, used to assign duties, give instructions, and provide feedback. Upward communication flows from lower to top management and is non-directive, used to provide feedback, inform about progress and problems, and seek approvals. Lateral communication flows between peers at the same level and is used for information sharing, coordination, and saving time.