Letter 566S is generally used for the audit of a specific item. Letter 566E is typically used for the audit of wages, withholding, and refundable credits.Tax audit letters will include your name, tax ID number or Social Security number, employee ID number, address and contact information. Example audit letters from the IRS and state taxing agencies. Sending an IRS audit reconsideration request? If you received a letter from the IRS, don't ignore it. Follow the directions on your letter, it includes all the information you need to respond. A legitimate IRS audit letter will always include the IRS logo, your taxpayer information, and specific details about your tax return. • A sample letter to request permission to use materials. • Copyright Notice to Students.