If you are looking to use vendor invoices and specifically approval workflow. You’ll need to work out who should approve the invoice. If they are expense type invoices then one option is to use financial dimensions. Based on the dimension allocated to the invoice then it would assign the approver as the owner of that dimension.
You can set this up with the vendor invoice expenditure reviewers. It will require some additional configuration like assigning an owner to a dimension value and configuring the invoice workflow to use the participant provider for vendor invoice expenditure participants.
Here is a quick overview.
AX2012 R3 CU11