This type of audit is the least threatening. You’ll probably never see an IRS employee; it will all be handled through the mail. Such exams are typically limited to a few issues that you can clear up by mailing copies of bills, checks, receipts or other relevant documents.

The only way an auditor can bet more information is to send you a letter asking for additional documents. Because you aren’t face to face with the IRS staff, you avoid the possibility of giving embarrassing answers or even volunteering information that might invite further exploration of your return.

To start the audit process, the IRS will send you a "contact letter" that spells out what the agency requires from you and the reasons you’ve been picked. These are the only items you must support with documents to avoid paying additional tax.

The letter also will tell you how long you have to respond, usually 30 days, before the IRS simply adjusts the tax in its favor (this means disallowing the items in question if deductions or adding to your income if the items in question are income items).

A correspondence audit doesn’t mean you’ll automatically have to pay more taxes. Many audited returns result in no change. Sometimes, taxpayers may even get money back when they realize they overlooked deductions.