Use discount.
https://quickbooks.intuit.com/learn-support/en-us/service-items/add-a-discount-to-an-invoice-or-sale...
This is is an enormous QB fail that customers can’t get a line item on an invoice for a credit memo or even a separate emailed credit memo. This is an awful workaround. It creates another account to be managed.
This isn’t a new issue. I’m sure you googled for solutions and found the frustration everywhere. Intuit neither fixes this nor justifies their failure to act. It’s mysterious why they would adopt such a customer hostile attitude.
