Thank you for your query.
Unfortunately there's no option for this as yet. But it can be a great idea for future releases. I'l pass this to the developers.
For now, you will have to create an item (type: Other charges) and add to the invoice as a new line.
You can actually add a
surcharge by editing certain tender functions Ifti such as Credit Card or
In the touch keyboard layout for example...
You can make this a $ or % and it will
trigger whenever you use the tender key that the surcharge has been applied to.
You can also add a surcharge to EFTPOS 'cash out' if you need to.