Setting up a mailer ID on the SendPro C Lite, SendPro C, SendPro+, SendPro C Auto

Your mailer ID is a 9-digit number that you need when using Electronic Return Receipt (ERR).
Products affected: SendPro® C Lite, SendPro® C, SendPro®+, SendPro® C Auto (2H00, 8H00, 9H00)

Your mailer ID is a 9-digit number that you need when using Electronic Return Receipt (ERR). 

To get a Mailer ID from USPS, visit the USPS Business Customer Gateway Mailer ID page. A Mailer ID is a unique number used to identify your business in USPS mailing systems. The page explains what a Mailer ID is, why it's needed, and how to apply. If you're new to this, it also guides you through setting up an account and submitting your request.

  1. Tap Settings.
    Settings icon
  2. Scroll down to the Envelope Printer Settings section.
  3. Tap Postage Refill.
  4. Tap Mailer ID.
  5. Enter the 9-digit number using the keypad.
  6. Tap Apply.

UPDATED: August 29, 2025