According to the IRS website, the IRS notifies taxpayers of an audit by mail or by telephone call. If notified by telephone, the taxpayer also receives a letter in the mail from the IRS stating the intent to perform an audit. The IRS never notifies taxpayers of an audit using email or any other type of communication.
An audit takes place at the IRS office or at the home or place of business of the taxpayer, according to the IRS. Prior to an audit, the taxpayer is notified of any documents necessary to conduct the audit. An audit may or may not result in changes to the taxes paid to the government. If any changes are made, they are detailed and explained to the taxpayer.
According to USA Today, three-quarters of all taxpayer audits are done in the IRS office, while the remaining audits are done in the field. Audits are performed based on randomized selection by computer, taking into account a number of variables, such as variations in income of a particular zip code, charitable giving and interest income. Document-matching to confirm that W-2 forms match the amount of income reported on a tax return is another common reason for audit.