You can add credit notes to customers; first, search for the customer you would like to add credit note to. Once you locate the customer's profile, click 'Quick links' in the top right corner.
This will bring up the quick links menu, select 'Raise credit note' from the financial subsection.
You will see a page where you can fill in the credit note. Fill in the form as required.
You can type the description of the credit note, e.g. labour reduction. You can also edit the date of the credit note and select whether you want your credit note to be broken down by category or be fully broken down into line items. Ensure you click 'Save' when you are finished.
Please note: when an invoice has been passed to a work address, the credit note must be raised within the invoice itself. To see how to do this please click here: Add a credit note against an invoice.