Your can print an invoice (or any other form) from ServicePal for iPad, if you have an AirPrint-enabled printer.
To print from the iPad.
1. Make sure your iPad is connected to the same local wireless network as your printer
2. From the job clipboard, open the form you would like to print.
2. From the action menu, choose "Print"
3. A PDF of the invoice will be generated
4. In the Printer window, select the Printer you would like to print to, and the number of copies needed.
5. Tap "Print"