'Remote areas' can be largely divided into Jeju Island and non-Jeju regions. You can setup the shipping fee when you register shipping location.
"remoteInfos": [
{ "deliveryCode": "CJGLS",
"jeju": "2500",
"notJeju": "0" },
Remote area shipping fee is separately charged for free shipping/conditional free shipping products also, but is not applied for products paid on delivery (furniture, direct shipping from supplier, etc.)
If the remote area shipping fee has been registered for a shipping location, it will be automatically applied during return as well (but only if the shipping fee is charged to customer/Coupang).