You can see the history of invoices by following these easiest steps:
1. Go to the 'Invoicing' on the toolbar and click on it.
2. You will find the table of invoices you've sent to your clients.
3. Click on the 3 dots menu of an invoice under the column of ' Action' and then click on 'View.'
4. Now look at the top of the page on the left side, you will find an option of 'History,' click on it.
5. You can now see the history of that particular invoice and by clicking on 'view all,' you can see the history of all the invoices you have sent (paid and unpaid both) under the heading of 'Activity Log.'