Tenn. Code Ann. § 36-5-1105: Reports on W-4 forms

Each report required by § 36-5-1102 shall be made on a W-4 form, or at the option of the employer, an equivalent form, containing the same data as required on the W-4 form. The report may be transmitted to the department by first class mail, magnetically or electronically in a format approved by the department.