CertificateOfMail allows you to quickly and efficiently prepare a Certificate of Mailing form 3665 manifest by importing a list of names and addresses that correspond to your mailpieces. It takes just three clicks of the mouse to import your list and print USPS form 3665. You are even able to provide additional information in an Internal Reference field with each address in your list, which then prints on the Certificate of Mailing form 3665.