There are two main categories of auditors. The first one refers to those who are from finance or accounting line. Normally, they perform accounting audits. They check the balance sheets and other relevant accounting data or documents. The main purpose of the accounting audit is to ensure compliance with the relevant accounting standard and legal requirements. The second category refers to those who are involved in quality or environmental management system.

The first category mainly focuses on the finance or accounting department of a particular company. On the other hand, the second category focuses on all the departments and sections of a company except for the finance department. They can be divided into internal and external auditors.

They carry out audits to find out if the company's system, procedures and processes comply with a specific standard, which is usually one of the ISO Standards. One of the most common ISO standards, which are used for business organizations worldwide, happens to be ISO9001: Standard.

Compliance to this standard gives a certain amount of confidence to customers or prospective customers in terms of a company's quality management system. A company, which is certified with ISO9001: Standard stands a better chance of striking a good business deal than one, which is not certified.

This is because the standard covers all the core business activities, which includes customer service, quality assurance of products or services, delivery and technology. So, a company that is certified with ISO9001: Standard has a better image in the eyes of prospective customers. ISO is actually an abbreviation for International Standardization for Organization.

To summarize, there are two key categories of auditors. One category is specialized in auditing finance or accounting areas of a company. The other category is specialized in auditing the whole company with the exception of finance or accounting. There are some differences in terms of auditing. However, both categories focus on checking the relevant areas for compliance with specific standard and other requirements.