Amazon’s beauty is that they will handle all logistics once your product is received into their warehouse. It's called FBA (Fulfilment By Amazon).
You send your inventory straight to them and they handle all the shipping and customer service and you get paid every two weeks.
The difference with eBay is that it is a send-it-yourself platform, so that would involve more work on your part. Amazon is also a significantly larger business with much more traffic and sales than eBay.