Currently, if you use FedEx by ShipStation to ship a package from the US to Canada, your customer is forced to pay customs clearance. That's a pain for customers. I prefer to collect an estimated customs fee from my customers when they buy stuff from me, then pay the customs clearance to FedEx/Canadian customs myself. That's called DDP. The shipstation docs make it look like you can choose DDP when using FedEx, but that's actually only if you provide your own FedEx account.
Until ShipStation offers this option, I'll keep shipping all my Canadian FedEx orders through Shippo, which has offered the DDP option for years and offers the same rates as ShipStation.
