The IRS is an agency of the United States' government that is responsible for tax collection and the enforcement of tax laws. Among the IRS' methods of enforcement is the use of IRS audits. An IRS audit is a formal review of the tax returns of an individual or a company. Individuals whose taxes have been reviewed have the right to appeal any decision of the IRS. This process begins when an individual receives a letter from the IRS detailing the suggested adjustments to be made to the individual's tax returns.