Go to Invoices and then select an Invoice from the Invoice Summary section.
You can edit any field on a saved invoice before the invoice is sent to a customer. After the invoice is sent, you can only edit the From information in the Header section and the Billing Contact information in the Billing section. If you realize you made an error after sending an invoice, you can cancel and create a new one.
After you have made your edits, click Save to save your changes.
