If you need to resend a document to a freight or 3PL company then this can be done 2 ways
First way is to do it from the Dashboard (this will upload all shipments for the order). Right click the order(s) and choose
The second way is to go into the order and go to the Shipment\Invoices tab, choose the shipment, right click, then select "Send to Freight Company"
You can go to the Files tab in the system and see the file that has been sent if you wish to verify it.