In each order in on the Awaiting Shipment page, there will be an Allocate button if that order has not been fully allocated (to the fulfillment process), you click on that to start the process.
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You can select the Qty to Pick of the items and click on Add Request button to create a picking request for that order. (note that there may be some ordered qty has been put into Backorder, and they cannot be allocated until you send them back to fulfill).
Qty need to pick = Assigned Qty - Prepare Ship Qty - Backordered Qty.
Prepare Ship Qty: Qty of items have been put into the fulfillment process.
Backordered Qty: Qty of items have been created backorder request.
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After the picking request is created successfully, a toast message will show “You have created a picking request successfully!”.