The issue here is that the notes on the invoice have white/blank spaces at the bottom of the message. If you get rid of these, the invoice will use 1 page, unless the message goes over to the next page.
To change the message you need to go to:
- Utilities - System Setup - Messages
- Open up the message for the invoice by clicking the ellipsis next to "number", and choosing the invoice type (e.g. if it is a Workshop Invoice, choose "Workshop Invoice Message").
- Click next to the last word in the message box
- Press the down arrow on your keyboard. If it moves to the next line, you need to delete this line.
- Press backspace to delete the above mentioned line.
Don't forget to press F2 to save the changes.