Hello, @jeff.jsjones.
To begin with, you should check the auto-credit feature in your settings to see if it is turned on or off. If it is turned on, this is likely the reason why you are unable to manually apply credit to an invoice, as it will be automatically applied once activated.
If you have verified that the auto-credit feature was turned off and you still cannot apply for the credit, you'll need to ensure that the credit memo is correctly assigned to the correct customer.
I'll include this article as a reference to learn how to check if the auto-credit feature is turned on or off and to understand the process of applying credits: Create and apply credit memos or delayed credits in QuickBooks Online.
Moreover, if you have followed all of my recommendations and are still unable to succeed, let's troubleshoot your browser. Sometimes, a browser can accumulate excessive cache that may affect the performance of QuickBooks Online. To start, try accessing QBO using incognito mode or a private window.
- Google Chrome: Ctrl + Shift + N
- Microsoft Edge: Ctrl + Shift + N
- Firefox: Ctrl + Shift + P
- Safari: Shift + Command + N
If this works, proceed to clear your browser's cache. This process will remove and fix specific issues and help the program run optimally. Additionally, you can use other devices and supported browsers to ensure everything works as expected.
Additionally, this article will help you on how we can personalize and add specific info to your sales forms: Customize invoices, estimates, and sales receipts in QuickBooks Online.
Please don't hesitate to reply to this thread should you need additional assistance applying your credit memo and any QuickBooks-related queries. We'll be right here to help.