The IRS says it initially contacts taxpayers about an audit by mail. The letter explains the examination and how to respond. Later telephone contact can be legitimate, but an unexpected call demanding immediate payment is not a reason to skip verification. [1]
What an audit letter usually asks you to do
An audit reviews information on a return. It may be handled through correspondence or through an interview at an IRS office, your business, your home, or a representative’s office. The request identifies the records or issues under examination. Read the complete letter before deciding what to send. [1]
Do not assume every IRS letter announces an audit. The IRS also sends notices about balances, identity verification, processing delays, and changes to a return. Search the CP or LTR number on the IRS notice and letter information page. [2]
Verify the notice before sharing information
- Compare the name, tax period, and return information with your records.
- Look up the notice number through IRS.gov.
- If something does not fit, contact the IRS through an independently verified number.
- Keep the envelope and every page of the letter in your case file.
Some notices can be viewed in an IRS online account, but an absent digital copy should not by itself decide whether a paper notice is genuine. Follow the IRS instructions for verifying an unfamiliar letter. If a voicemail follows, use our IRS voicemail verification process. [2]
Build a response around the requested issue
Create a folder for each tax year and a separate list of requested items. Put a short explanation beside each document so the reviewer can connect it with the relevant entry on the return. For a business expense question, for example, organize the invoice, proof of payment, and explanation of the business purpose together.
Send copies through the authorized channel, keep your own complete response packet, and preserve delivery or transmission records. If a fax number is supplied, use it only for the requested submission. See when the IRS permits faxed documents for the distinction between a case response and filing an original return.
Track the deadline separately from the discussion
Respond by the date in the letter. If you need more time, contact the assigned office promptly. The IRS describes extension procedures for some correspondence audits, but a routine document extension does not extend a statutory deadline for a court petition. Read any later formal notice on its own terms. [1][2]
A useful working calendar has three entries: the response due date, the date you plan to finish gathering records, and the date you will confirm submission. This leaves time to correct a missing attachment rather than discovering it on the last day.
Do you need a representative?
You have the right to retain an authorized representative and to challenge the IRS’s position. Consider the complexity of the issue, the amount involved, and your ability to organize the records. Our guide to eligible IRS representatives explains credentials and the authorization process. [3]
An examination is a request to substantiate or review the return; the letter alone does not establish the final tax result. If a balance is ultimately due, evaluate payment plan options separately from your decision about whether the proposed adjustment is correct.
Primary sources
Sources checked: October 31, 2026.