How do I handle a prepayment?

[dbcTech]

First you should create an Invoice for a zero dollar amount with no
lineitems. Then, enter the information on the payment line as you
normally would. When you are ready to invoice the customer you have
two options. If you have not closed the period that the invoice with
the prepayment is in, you can simply enter the lineitems to the
invoice that you created for the prepayment. You may also want to
change the invoice date to reflect the date the customer was actually
invoiced. The other option which is more common is to create a new
invoice for the customer with no payments. Then go into Receive
Payments on the Customers and use the zero payment function as
explained in the manual.