Hi Deepak,
If you create an own workflow type which is not already in Dynamics 365, then for the workflow itself, you don't have to check the licensing guide.
E.g. if you create a workflow for project detail changes, this is not part of the standard application and you don't need a license then. If you want to create another vendor invoice workflow, then you have to align with the licensing from Dynamics 365 for the approval part.
Having said that, the users will need to have at least view access to the form which initiates the workflow. Depending on the licensing guide and menu item used, this will require the license type for your user. There can be a difference in the license requirement if the user will get maintain or view permissions.
