Motivation theories can be categorized as either content theories, which focus on internal factors like needs and emotions, or process theories, which examine how motivation influences behavior. Key content theories include Maslow's hierarchy of needs, Herzberg's two-factor theory, and McClelland's acquired needs theory. Important process theories are Vroom's expectancy theory, goal setting theory, and equity theory. These theories provide frameworks to understand what motivates individuals and how their motivation can be influenced.