How do I enable FedEx One Rate pricing?

In ReadyShipper Pro, on the left sidebar under Settings click Shipper Accounts. Select your FedEx Account. On the right under Settings and Defaults, make sure Default FedEx One Rate is checked off.

Note: FedEx One Rate pricing is only available to applicable FedEx Express shipping methods using FedEx Express tracking. You cannot use your own packaging when shipping via FedEx One Rate.