If you know the number of the delivery note, simply open the delivery note input window and enter the number to retrieve the delivery note.
There you can see the invoices for that delivery note on the "linked target doc" tab.
On the tab “Gelinkte basis doc”, you can see the offers or orders for which this delivery note was created.
If you don't know the number, but you do know the customer, you can access the customer's card via the “Verkoopdoc.” select all delivery notes for that customer.
Double-click on the delivery note of which you want to know the invoice.
The screen for entering delivery notes opens and there you will find the linked documents for that delivery note as described above.