External auditors are not employees of the companies that they audit and are instead independent contractors. They will analyze and interrogate a company's financial information to look for evidence of fraud or irregularities and produce a report with their findings. External auditors will be expected to be a member of a recognized professional accountancy and will usually present their findings to a company’s shareholders.
You will be expected to have a bachelor's degree in accounting or a similar field will be expected to be a certified accountant, and will be expected to have years of experience as an auditor.
