39 C.F.R. § 223.2 – Channels of communication, headquarters with area offices.

(a) General. Headquarters organizational units formulate the directives to provide guidance to area officials.
(b) Policies. Policies are issued over the signatures of the vice presidents of the functional organizations (unless the postmaster general or deputy postmaster general issues these directives personally). Whether published on paper or online, such policies must be coordinated with other appropriate organizations before issuance, and reviewed, published, and managed by Public Affairs and Communications. If within the authority of the issuer, these policies have the same effect as though sent by the postmaster general or deputy postmaster general.
(c) Procedures. Regulations, instructions, and implementation guidelines are issued over the signatures of vice presidents of functional organizations or their accountable functional unit managers and used to implement programs and business activities. Whether published on paper or online, such procedures must be coordinated with other appropriate organizations before issuance and reviewed, published, and managed by Public Affairs and Communications.
Inspection Service Requirements