Fulfilling the order is the process of sending the purchased items to the sender. In the case of physical goods, it's when the items are shipped. In the case of digital items, it's when the sender downloads the product.
Some business policies charge the sender as soon as they commit to making the purchase. If
this is your policy, use a Pay request to authorize the payment. No
further interaction with Amazon FPS is required. This section does not pertain to those
businesses implementing that policy.
Other business policies charge the sender's payment instrument when the order is
fulfilled. If this is your policy, use a Reserve request to authorize
the payment and then, later, use a Settle request to authorize the
payment. The following sections help you develop that process.