Updating a Purchase Order (PO) on your invoice can easily be done in T3. It should be noted that when updating the PO on an invoice, the changes will apply to that particular invoice only, not other invoices tied to the rental order.
Log in to T3.
Access the Fleet web app from the navigation bar across the top.
Select Billing from the left menu.
Select the invoice from the table to open.
On the top right, click the Change button under Purchase Order.
The Add or Edit Purchase Order screen will display. Make your changes and select Save.