26 CFR § 31.6011(a)-9
Instructions to forms control as to which form is to be used
June 25, 2020
Notwithstanding provisions in this part which specify the use of a particular form for a return or other document required by this part, the use of a different form may be required by the latter form's instructions. In such case, the latter form shall be completed in accordance with its instructions.
[T.D. 7351, 40 FR 17145, Apr. 17, 1975]