We have got a following problem:
some clients pay advance payments; how do we add that in the invoice, subtracting from the total and having the balance at the bottom?
Once you created an invoice you should Edit it:
Add new line to your invoice:
When you add a new line to your invoice:
You can select or type percentage, or enter a fixed amount and enter description of the line:
That's how simple it can be done.
All the best