Any supplier invoice entered onto the system can be chosen to be produced as a self-billing invoice.
In the supplier record you will need to ensure that the VAT number and address of the supplier has been populated.
The supplier invoice will need to be entered as normal.
Once the invoice is entered onto the system, go to Suppliers | Supplier invoices.
From this screen, select the green button with 3 white dots under 'Actions' and select 'Self Bill'.
This will produce a PDF document which can be printed, or saved and emailed as required.