Also, say you own a small business. You sell candles. Someone orders one of your Christmas candles. They call two weeks later because they haven't received their order yet. That is, their order hasn't been delivered by the postman yet. You can say to the customer, "I shipped/sent out your order last week. It should arrive / be delivered soon." So "to send (something) out" = "to ship (something)" in this context and "to arrive by means of a postman" means the same as "to be delivered (by a postman)" in this context. :)

To ship emphasizes when the product leaves the source, and to deliver emphasizes when the product arrives at the destination.

If something it has been shipped, then it could be delivered (at destination). If shipping has not been done, then delivering will never happen. /to ship/ is an action done by the seller, /to deliver/ is an action done by the carrier.