post
https://api.ecartapi.com/api/v2/orders//fulfillments
"logisticMode": "seller-Ecommerce" is required if you're using the fulfillment creation request where you will generate the shipping label (i.e., third-party shipping, not handled by Temu).
To obtain the "companyId", you'll need to make a request to Get Carriers.
items.id corresponds to the product ID within the order. Both the ID and the quantities must match the information in the order.