To report on the Credit Notes that have been generated directly from the Invoices completed for your customer Sales Orders you can use the Credit Enquiry or Invoice Enquiry.
Include Credits on the Invoice Enquiry
To populate Credit Notes, not including Free Credits, on the Invoice Enquiry:
Head to Reports > Sales > Invoice Enquiry.
Use the filters available to refine your report, e.g. Date, Customer or Sales Order Group.
Tick the Include Credits checkbox.
Click Run.
Each Credit that has been generated from an Invoice and aligns with the filters set in the Invoice Enquiry will be populated.
Include Invoices on the Credit Enquiry
The Credit Enquiry will populate all Credit Notes and Free Credits that have been created in your account. To review the Credits and identify the original Invoice a Credit Note has been made from, add the Invoice Number column into the Credit Enquiry's grid.
To add the Invoice Number column to the Credit Enquiry:
Head to Reports > Sales > Credit Enquiry.
Click on Show Toolbar, and select Hidden Columns.
Drag and drop the Invoice Number header into the grid layout.
Apply any necessary filters to the Credit Enquiry.
Click Run.
The Credit Enquiry will display each Credit's original Invoice in the Invoice Number column. If the Invoice Number column is blank, the credit is a Free Credit and does not directly link to an Invoice.