26 U.S.C. § 7522 — Content of tax due, deficiency, and other notices

(a) General rule. Every notice covered by this section must explain why you owe money. It must describe the basis for the tax. It must state the amount of tax due, if any. It must state the amounts of interest, additional amounts, additions to the tax, and assessable penalties, if any of those apply. If the notice explains these things badly, that alone does not make the notice invalid. (b) Notices to which section applies. This section covers three kinds of notices. First, a tax due notice or deficiency notice described in section 6155, 6212, or 6303. Second, any notice that comes out of an information return matching program. Third, the first letter proposing a deficiency that gives the taxpayer a chance for administrative review in the IRS Independent Office of Appeals.