You can create either an email (non-returns) shipping label or an email returns shipping label by using the ShipService CreatePendingShipment Request. You can also cancel either of these requests by using the ShipService CancelPendingShipment Request.
The Email Return Label option allows you to email a return label directly to your customer. Your customer can then print the label, apply it to the package, and call for pickup or drop the package off at the nearest FedEx drop-off location. For your customer’s convenience, the email also includes links for scheduling a pickup and finding drop-off locations in the area.