The new Workflow 2.0 that we introduced in Dynamics GP 2013 R2 and continues through Dynamics GP 2018 is a hybrid of sorts, combining the Requisition Management from Business Portal with the old Workflow for Dynamics GP that was installed on SharePoint.
In each company database, you will create workflow 'hierarchies' and those workflows are specific to that company they are created in, they are not system-wide.
The new Workflow does use Active Directory user accounts and not the GP logins, so potentially, you could create a domain group in AD and assign approvers to it, then specify that AD group as the approver in the workflow steps.
Some differences with the 'hierarchy' in Business Portal and the new workflows, is that we no longer set user-specific settings, such as we no longer can set a monetary limit on a user as to what they can approve and not approve or what they see.
In the new Workflow 2.0, it's more setting up approval conditions for a purchase requisition such as having it require approval when the requisition is requested by a specific GP login or the requisition is over a specific sub-total, then you assign approvers to each step.
Workflow steps can follow one-another or be unilateral to each other, depending on how the customer wants it.
I would recommend starting with the following blogs:
WORKFLOW 2.0 FOR MICROSOFT DYNAMICS GP 2013 R2 – An Overview
community.dynamics.com/.../workflow-2-0-for-microsoft-dynamics-gp-2013-r2-an-overview
Workflow 2.0's Workflow User Setup window options: part 1: People and Groups
community.dynamics.com/.../microsoft-dynamics-gp-2013-r2-workflow-2-0-39-s-workflow-user-setup-window-options-explained
Workflow 2.0's Workflow User Setup window options: part 2: Hierarchy
community.dynamics.com/.../workflow-2-0-39-s-workflow-user-setup-window-options-part-2-hierarchy
Workflow 2.0's Workflow User Setup window options: part 3: Workflow Role
community.dynamics.com/.../workflow-2-0-39-s-workflow-user-setup-window-options-part-3-workflow-role
We have a good amount of blogs related to Workflow 2.0 published and that is where the majority of our new information and documentation is published, so if you're not already doing so, I would follow the community.dynamics.com/gp blog site and you can search there for more blogs specific to the new Workflow 2.0, including On Demand videos on setting up workflows, such as setting up a purchase requisition/purchase order workflow, which you can find at this link:
community.dynamics.com/.../on-demand-learning-requisition-purchase-order-workflow-setup-and-overview-for-microsoft-dynamics-gp-2015
Thank you,