In hibooks, you can allocate a Credit Note to an invoice. You can only allocate from a credit note if it is unpaid. Learn how to Create a Credit Note and how to add a Credit Note to an Invoice.
How do I Allocate a Credit Note ?
First, you must click on Sales form the side bar menu and then Invoices from the drop-down menu.
Select the credit note you wish to allocate.
Click on the button with three dots and then on Allocate Credit Note.
Enter the amount you want to allocate to the corresponding invoices.
Click on Save when you are happy with the amounts allocated.