Understanding How it Works with WooCommerce
The way WooCommerce Amazon Fulfillment works is that it silently monitors WooCommerce in the background and detects when an order has been completed and paid for. Then, it takes that order information and looks for products that you have set to fulfill with Amazon. It will send the data for those products by SKU along with the order information like shipping address to Amazon Fulfillment where FBA then takes over and ships the items. WooCommerce Amazon Fulfillment will detect any errors with the FBA shipping request like if a SKU is out of stock in Amazon, create an Order Note about the issue, and send you an email about the problem.