You have to search for the related shipment (using the relate button on the sale) or by opening the Customer shipments menú. You can send the goods from there.
In case of purchase, you have to open the supplier shipments menu, create a new shipment pick the right supplier and you will be able to see the pending moves of the supplier ussing the + button of the incomming moves field.
From there you can pick the moves that you want to receive and use the “Receive” button to confirm the action.