Archived orders are not returned in Fulfillment getOrders API
The "getOrders" API, which is utilized by sellers to retrieve their orders, possesses a distinct behavior with regard to archived orders. The orders that have been archived by the seller will not be included in the getOrders response. Consequently, if you find that certain orders are missing from the response you receive, It is advised to pay attention to the "Archived" section within the seller hub.
Note: The Fulfillment API covers only the transactions that have completed the checkout process. This API does not cover pending payment purchases that require upfront payment before shipment.