This field shows how many units of the item on the line have been invoiced.
If the entry is both a shipment or receipt and an invoice, the quantity will be the same as in the Quantity field.
The field can be filled in from the following fields:
If the entry was posted from an item journal line, the quantity is copied from the Quantity field on the journal line.
If the entry was posted from an invoice or credit memo, the quantity is copied from the Quantity field on the sales or purchase line.
If the entry was posted from an order, the quantity is copied from the Qty. to Invoice field on the sales or purchase line.
If the entry resulted from the production of a BOM (bill of materials), the quantity for the BOM itself is copied from the Quantity field on the BOM journal line. For the entries for the items that comprise the BOM, the quantity is retrieved with the item number in the BOM Component table.