To write off an invoice in QuickBooks, open the customer's transaction. Click "More" at the bottom and select "Void" or "Delete." Confirm the action, and QuickBooks will delete the invoice from your accounts receivable, effectively writing it off.Run the QuickBooks File Doctor tool or speak with QuickBooks support just dial us at +1(855)-738-0359.if the problem doesn't go away if you do any of those things.