You can manage the fulfillment yourself or outsource it to a third-party logistics firm (3PL) that specializes in eCommerce order fulfillment.
It’s simple, you control your orders and make sure that you are able to deliver. It is essential to keep your orders in order and keep the delivery on time to avoid problems with your customers as well as with Amazon itself.
Important to note that you’ll handle returns too and this can add to the requirements for customer service.
As of the spring of 2022 Amazon was still on a waiting list in its Seller Fulfilled Prime program, which allows sellers to fulfill their own orders, and receives the Prime badge for their products when they fulfilled the requirements for delivery.