If you are notified that you will be audited, first resist the impulse to panic. An audit simply means that some items on your return seem questionable, and the IRS wants you to clarify them. As long as you prepared your return correctly from the documentation you have, and retained that documentation as proof of your income and deductions, you should not have a problem.
The majority of IRS audits are conducted through the mail. For example, they will ask you to prove a deduction, and you send them a photocopy of that proof. (Note: NEVER send your original documentation to the IRS or let them keep it in an office audit. Provide copies ONLY.) Other audits might be conducted at an IRS office, or at your home or business.
In either case, you should only need to provide information about the specific items that the audit notice lists as in question. Do not “volunteer” any additional information that is not being questioned. If your return was prepared professionally, it would be wise to consult with the preparer for additional guidance.
If you have an in-person audit, you have the right to have an advisor accompany you or, in the case of a CPA, enrolled agent, or attorney, appear in your place as your representative under a Power of Attorney.