If you check the "Print blank invoices" option on the Schedule Print Options screen (see below), H2OS will print one partially prepared invoice for each job in the schedule for job types selected there.
A sample partially prepared invoice:

The format of the invoice is determined by a separate "report definition" file.
When a "print invoices" option is checked, the target printer name (that will print the partial invoices) will appear below the print invoices options. This allows you to print invoices on one printer and the summary and detail job tickets on another.

When an invoice prints out for a customer that has a separate Job-Site address (From mailing address) , the mailing address is used on the Invoice. As I mentioned, this appears fine on the surface. However, in practical use it is necessary to match the invoice. To resolve this, the invoice now includes “Job-Site: <Job-site address>” .

Note that the USE THIS WORK SITE ADDRESS is checked

1. The invoice print format definition is stored as c:\h2os\reports\h2os_invoice_1.frx
A sample/test invoice returned to the office after completion in the field

See sending invoices to QuickBooks