This lesson will explain the process of downloading an existing template, adding 2 extra fields and then re-uploading the template back to ServiceM8.
Go to Settings

The first main step is to download the standard template to your computer.
Click Document Templates

Download the template by clicking "click here"

Save the template

Open the Template

Select two cells rows, right click and choose Insert > Insert Rows Below

Type in the field descriptions

Now copy <<job.total_price>> merge field into both new cells

Right click on the merge field next to 'Amount Paid' and click Edit field

Change the field name to 'job.amount_paid', then click Ok

Do the same to 'Balance Due' and use 'job.balance.due' merge field

For the full list of field codes go here: http://support.servicem8.com/entries/388498-What-fields-are-available-for-the-Invoice-Quote-Work-Order-templates-
You may need to reset the font

Save the document

Go back to ServiceM8 Document Templates and click Upload Custom Invoice Template

Click Select and find the template then click Attach

The template now includes both 'Amount Paid' and 'Balance Due'

If you are using MS Word for Mac, refer to this article - How to create a merge field on Mac.