1. Large multinational companies: Large multinational companies usually have complex organizational structure, huge staff, diversified business scope and extensive international business, which makes the internal audit of large multinational companies difficult and challenging.
2. Manufacturing companies: The internal audit of manufacturing companies involves procurement, production, sales and other links, and the audit of these links can be used as the research object of this paper.
3. Financial industry companies: The internal audit of financial industry companies involves risk management, investment decision-making and other links, and the audit of these links can be used as the research object of this paper.