Record goods leaving the warehouse for a customer — stock on hand decreases automatically.
The delivery note is the sales-side twin of the purchase receipt from the procurement cycle — it's the document that actually moves inventory, this time downward, when goods physically leave for a customer.
A sales order alone doesn't touch quantity on hand — it's a delivery note that does. This is also the point where Redovix checks whether you actually have enough stock to fulfill the order; if you don't, and "Allow negative stock" is off (the default), the delivery is blocked rather than silently going negative.
As with receiving goods, the shipped quantity defaults to the full ordered amount but is editable, so a partial shipment against a larger order is a normal, supported case — the sales order stays open for whatever's left.