Sending Invoices and Statements
It is a USPS requirement that Invoices and Statements be sent via USPS First-Class Mail.
The following information is from the USPS Domestic Mail Manual regarding Marketing Mail. Marketing Mail is the new name for Standard Mail which is the equivalent of Bulk Mail. USPS First-Class Mail has no other name and should not be referred to as Bulk Mail or Standard Mail.
2.0 Content Standards for USPS Marketing Mail
2.1 General USPS Marketing Mail consists of mailable matter that is neither mailed nor required to be mailed as First-Class Mail and that is not authorized to be mailed as Periodicals (unless permitted or required by standard) and that weighs less than 16 ounces.
2.2 Personal Information Personal information may not be included in a USPS Marketing Mail mailpiece unless all of the following conditions are met: a. The mailpiece contains explicit advertising for a product or service for sale or lease or an explicit solicitation for a donation. b. All of the personal information is directly related to the advertising or solicitation. c. The exclusive reason for inclusion of all of the personal information is to support the advertising or solicitation in the mailpiece.
2.3 Bills and Statements of Account Mail containing bills or statements of account as defined in 233.2.2 may not be entered as USPS Marketing Mail except under the conditions described in 2.5.2.