To set-up a shipping method with a UPS, FedEx, or USPS service option, please follow the steps below.
1. Go to Configurations -> Shipping Methods -> then click on +New Shipping Method.
2. Fill-up the Name field (e.g FedEx, UPS, USPS), choose the Shipping Categories, Zones and Tax Category. Also, choose the calculator from the drop-down field. Once done, click on Update.
This is how the Calculator list looks like.