Dropshipping lets you sell products by using a supplier that holds the inventory and ships the product for you. You pay the wholesale price to the supplier, while controlling the price that your customers see in your Shopify store.
When a customer places an order in your store, you purchase the products from the supplier and select how to ship the product directly to your customer. You don't need to hold any inventory or ship items yourself.
Products are the most important part of your dropshipping business, the products that you choose to sell will shape how you run your online store, how you market your store, and who you market it to.