Firstly it is recommended that your default payment terms are created initially and once this is done, they need to be applied to the booking or quote when generating invoices. If you do not have payment terms and require all moneys up front, you can just do a final invoice and skip the payment terms setup.
To apply payment terms to a booking or quote:
Navigate to Bookings > Bookings and edit a booking or...
Navigate to Sales > Quotes and edit a quote.
Go to the “Payment Terms” tab
Click “Add payment” terms
If you wish to add a pre-existing default payment term to the booking then select existing and select the appropriate booking term, this will load in all of your deposit, balance and payment options against the booking.
If you have negotiated a special payment term with the client, the select “new” and set up the payment term appropriately.