After setting up the layout, you may want to add an additional field with information such as 'payment term', 'an alias name', or 'article layout'.

To add an extra field to the invoice, you first need to add it via "Settings" > "Advanced" > "Extra Fields".

Then, update the default field and further fill in the values.

If you wish to update the field, click on 'actions' and update it.

Attention: To see these additional fields appear on the invoice, you'll need to make one more adjustment. Go to 'layout' > 'document details' and select the fields you created in 'settings'.

The fields you've added will now be visible on the invoice, and you'll be able to fill in the value when formatting the invoice.