In order to create an invoice from the delivery note, click on the Create invoice option from the delivery note details menu. 
The option is available only for the approved delivery notes.
Select the invoice currency and then click on the [CREATE] button.
When the invoice is created:
- The date of the invoice is set to current date.
- The category is set to invoice.
- Some data that is copied from the original delivery note:
- Basic information - partner, and department.
- Invoice items - items and quantities are copied from the delivery note.
- All items for the delivery note are listed together in the invoice.
- The total amount for the invoice will be calculated automatically based on the defined unit price , discounts and VAT.
- Link to the delivery note is visible at the bottom of the invoice Details/Edit page.
Note: The color of the delivery notes which has invoices is changed to gray in the delivery notes list.