How can I add a custom/external carrier account? (FedEx, USPS, UPS)
Adding An External Carrier
If you have a relationship directly with UPS, FedEx, or USPS you can add that account and use it to process labels. Here is how:
Billing & Processing Orders
If you are using your own carrier account you will not be charged for the shipping cost of the package, you will only be charged a small label fee for each label generated. The shipping rates and other fees related to external carrier accounts will be charged directly to you by the carrier.