In order to integrate with Stamps.com, please follow the below steps
Search Path: Setting - Integration - Carrier Setup - Add - Stamps.com
Click "Carrier Setup" under "Integration"
Input the Basic Information and Integration Information and click "Confirm"
(Please see the below description)
Nick Name: Input the carrier name
Pickup Address: Select a pickup address or leave it empty if there is no restriction on the address
Username: The username for Stamps.com
Password: The password for Stamps.com
The connected stamps account is now available on the page