Human resource management involves acquiring, developing, motivating, and maintaining human resources in an organization. It is a critical management function that must adapt to changes in the internal and external environment of organizations. Key aspects of the internal environment include organizational goals and policies, culture, and reward systems, while external factors include technological advances, workforce diversity, globalization, and legal trends. HR management plays several important roles in organizations, including as a line function, staff function, representative, coordinator, mediator, strategic partner, and integrator.