Group communication is used for sharing information, collecting feedback, and making decisions on important matters. There are two categories of group discussion - organizational discussions for tasks like brainstorming, and selection processes where discussions are used to evaluate candidates. Group discussions evaluate candidates on knowledge, communication skills like active listening and expression, group behavior, and leadership. They can be based on topics or case studies. Meetings are used for informal purposes like sharing information or exploring ideas, and decision-making like solving problems or reaching agreements. Proper preparation includes allowing time, setting duration and agenda, and choosing a venue.