This report provides a comprehensive overview of different types of companies and their functions within a business context. It begins by differentiating between various company sizes, including micro, small, medium, and large businesses, highlighting their characteristics and operational aspects. The report then delves into specific business structures, such as sole traders, partnerships, limited liability businesses, public limited liability businesses, and cooperatives, detailing their unique features, advantages, and disadvantages. Furthermore, it examines the influence of external factors, such as inflation rates, exchange rates, and demographic shifts, on business operations. The report also incorporates a PESTLE analysis to assess the political, economic, social, technological, environmental, and legal factors that impact business performance, providing a holistic understanding of the business environment. The report uses the example of Mark and Spencer to demonstrate real-world applications of the concepts discussed.