After invoices have been sent or manually marked as sent, they cannot be deleted. If there are any invoice discrepancies that need to be corrected at this point, you can do so by generating a credit note. This effectively reverses the invoice and is how you can "delete" sent invoices.
- Navigate to Invoicing.
- Switch to Action Invoices.
- Select invoice(s) in Sent or Sent manually status. Create Credit Note button will appear under the Actions dropdown.
- Click on Create Credit Note button, Credit Note generation process start and display operation progress page.
- After generation, you are taken back to the Action invoices screen from which you can select and send the credit note(s).