The customer creating the Intercompany transactions manually in the pending vendor invoice form and they wants to use the Vendor Invoice Automation feature to submit automatically to the workflow.

Currently this feature only allows the transaction which are imported. I have gone through the below links for more details.

https://docs.microsoft.com/en-us/dynamics365/finance/accounts-payable/auto-vendr-invc-process
https://docs.microsoft.com/en-us/dynamics365/finance/accounts-payable/vnd-invoice-set-up-options