First you need to create a custom form to use as client invoice:
- Download the attached 'Client Invoice' template.
- Open Forms under Administration.
- Click on 'New'.
- Enter 'Client Invoice' as name.
- Select the template you downloaded in step one and then click OK.
After you create the template open any case with billing information and then click 'Send Doc'. From the list of document select 'Client Invoice' which should be located under Misc. Then email, print or fax the invoice.