Workflow by company

Can I create different workflows for same doctybe separated by company I mean each company on the system have his own workflow status and steps for the same DockType such as purchase order

Sure, just give the proper conditions in the respective actions of the workflow.

Conditions could either be == “” (if the document has a company field.)
If the doctype does not have a company field, you could also try to use session defaults via (not sure on this one.)