Can i delete a credit note made by mistake

I'd be glad to help you in deleting a credit note that was mistakenly created in QuickBooks Online (QBO), elizabeth. 

If you've created a credit note in QuickBooks Online by mistake, you can delete it by going to the Sales menu. 

Here's how:

1. Click Sales, then choose Customers.
2. Scroll down, find the customer whose Credit Note you'll delete, and click their name.
3. Find the transaction in the list below and click to open it.
4. Click More at the bottom of the Credit Memo screen and select Delete.
5. Select Yes to confirm the deletion. 

You can also check this article for more information about credit notes: Create and apply credit notes or delayed credits in QuickBooks Online.

I've included articles on how to handle customer refunds and record overpayment as a tip in case you encounter such a situation in QuickBooks: Handle a customer credit or overpayment in QuickBooks Online.

Don't hesitate to add a reply in the comment section if you have clarifications about deleting credit notes in QBO. I'm always here to help. Have a great day.