I guess that varies from seller to seller. If the seller is sending the item to you by VPP, then it will be the post man.
However, if the seller is using a courier service like Aramex, then it will be Aramex's delivery person.
I doubt the seller will be sending his / her executive to deliver an item, but then it really varies from seller to seller, so your best bet is to contact the seller directly.
Hope this helps.