Listed by Universal Postal Union Number

International mail is mail that originates in the United States for delivery in a foreign country or mail that is addressed for delivery in the United States that originated in a foreign country. Member countries of the Universal Postal Union (UPU) have agreed to use certain documents in the processing and delivery of mail. In conjunction with that agreement, the Postal Service uses both directives and forms to help process and deliver international mail. As a reference, the following table lists the Postal Service documents that have a UPU identifier.