Firm Mailing Book For Accountable Mail - USPS
about.usps.com › forms › ps3877For Registered Mail and COD, the mailer submits the forms in duplicate and receives one copy as the mailer’s receipt after the USPS employee accepting the mailing has verified the entries. For Certificates of Mailing with domestic or international mailings, the mailer must use either PS Form 3665, Certificate of Mailing – Firm, or PS Form 3817,