If you are on version 7.6 or higher, and using the ECIs PO Processor/PO Receiver, there is integration for those products with certain vendors - more here
1. The receive option will create a shipment record and also post the Tracking number on the shipment record
2. There is an eAgent task that can optionally be used to fulfill the SO (POP doesn’t do that directly)
3. The PO Remarks get the Tracking number and also the Shipment record for the SO
These are the current vendors supported in POProcessor that will write back the tracking numbers to eAutomate.
Parts Now (their technology is a bit dated so this isn’t the best integration)