Who is responsible for "loading" the cargo onto the truck?

I've only done small parcel delivery through Amazon shipment, but I'm preparing for LTL pallet shipment now. Our warehouse does not have a loading dock, so apparently, I have to create a support case to request lift gate(https://sellercentral.amazon.com/help/hub/reference/GM9THX2S47XTGJTQ).

I was wondering who's technically responsible for loading the pallet to the truck especially if we're to use a lift gate truck? Do I have to load the pallet with my pallet jack to the driver's truck? I'm thinking about giving a small tip for the driver to move a couple pallets from my warehouse to his truck, but I'm not sure whether it is conventional or generally a good idea.