#Update Stock Option in Sales Invoice The Update Stock check box is available in the Items section within Sales Invoice form. Usually the Sales Invoice is a voucher specifying the amount to be paid against Quantity delivered/to be delivered as per a particular Sales Order. Checking the update Stock option before submitting an Invoice will directly deduct the Stock from the Inventory on submission of the Sales Invoice. In such a case the Sales Invoice also satisfies the function of a Delivery Note.