Welcome to the Community, @ghibouryan.
I'd be glad to help you out by sharing possible scenarios I could think of.
Are you trying to void or delete a customers invoice? If so, I'd be glad to walk you through the steps on how to void or delete an invoice. Here's how:
- Open the invoice transaction.
- Click More.
- Choose Void or Delete.
- Select Yes to confirm.
Here's an article for your reference: Void or Delete an Invoice, Bill, or other Transactions.
But if you're referring to an invoice that becomes uncollectible, you'll need to record it as a bad debt and write it off. Feel free to check out this article for the detailed steps and information on how to record a bad debt: Write off Bad Debt.
Feel free to leave a comment below if you're referring something else or if you have any other questions. Have a good day!