I stuck in an strange issue, and was unable to resolve, I goggled and was unable to find any blog, knowledge base, or any other help. Actually I was in middle of creating a workflow for Vendor Bank Remitance and was unable to complete it as I wan unable to add any place holders.
I created a new legal entity, and tried to create same workflow and field was there. When I looked at in more details I found out that form is based on current language. I just navigate to Organisation Administration > Setup > Organisation > Legal Entities > Remove the language > Closed the form and re-add language as en-us.
It resolved the issue, Hope this helps any one out there.