There are different ways you can identify the status of your PO-based invoices.
Option 1: Go to the specific Purchase order, under the Invoice tab you will see all the invoices created against that Purchase Order. The Generated tab shows all the submitted Invoices. The IN PROGRESS tab shows all the invoices in draft and REVERSED tab shows all the rejected invoices.
Option 2: Use the global search option.
1. On the Dashboard, a search box appears on the top right.
2. Enter the Invoice number and click on search icon.
3. You will get to see the Invoice with the status and other details.