Mailing Standards of the United States Postal Service Domestic Mail Manual > 100 Retail Mail Letters, Cards, Flats, and Parcels > 110 Retail MailPriority Mail Express > 114 Postage Payment Methods
Overview
1.0 Basic Standards for Postage Payment
[1-24-21] Retail Priority Mail Express postage may be paid with adhesive stamps (see 604.1.0), postage evidencing systems (see 604.4.0), or with USPS Click-N-Ship. The mailer is responsible for proper payment of postage.
[1-24-21] Any postage evidencing system may be used to prepay reply postage on Priority Mail Express shipments under 604.4.5.2.