If an invoice is incorrect it can voided, this will remove it from the financial reports.
Navigate to Sales > Invoices
Click on the All filter.
Click on the invoice number of the invoice that you would like to void.
Click on the Void button and confirm when prompted.
If there are any payments allocated to the invoice you will be prompted to delete either the payment or both the payment and the invoice. In this scenario, you will need to click on the Delete All button.
All voided invoices are listed in the Void tab under Sales > Invoices