Amazon is a prime example of an e-commerce website.
You browse products in the Amazon store, order the ones you want, pay by credit card and they get delivered. You have confidence in the process.
But Amazon makes no product and they sell through an army of affiliates. Some products they stock (FBA - Fulfilled by Amazon) and the rest is drop shipped by their suppliers. With drop shipping, you don't have to store any inventory. You advertise product, your customer orders and pays for it and you order it from the supplier, who ships it to your customer.
It all works smoothly for Amazon because they have software and systems in place to handle it all. Well, guess what? You can do the same. You can create an e-commerce website. This is how.