26 U.S.C. § 6014: Income tax return—tax not computed by taxpayer

An individual who does not itemize his deductions and who is not described in section 6012(a)(1)(C)(i), whose gross income is less than $10,000 and includes no income other than remuneration for services performed by him as an employee, dividends or interest, and whose gross income other than wages, as defined in section 3401(a), does not exceed $100, shall at his election not be required to show on the return the tax imposed by section 1. Such election shall be made by using the form prescribed for purposes of this section. In such case the tax shall be computed by the Secretary who shall mail to the taxpayer a notice stating the amount determined as payable. to cases where the gross income includes items other than those enumerated by subsection (a), to cases where the gross income from sources other than wages on which the tax has been withheld at the source is more than $100, to cases where the gross income is $10,000 or more, or to cases where the taxpayer itemizes his deductions or where the taxpayer claims a reduced standard deduction by reason of section 63(c)(5).