With the release of the Microsoft Dynamics GP 2018 July Hotfix you now have the option of using Azure Active Directory Organization Accounts for the originator, approver and manager roles in Microsoft Dynamics GP Workflow.
Making Azure Organisation Accounts work with Workflow for originators, approvers and managers now means that Workflow can be used in pure Azure environments which do not have a traditional Domain Controller available.
Lucas Miller on the Dynamics GP Support and Services Blog has a blog post running through the steps to configure and install the necessary components to use this new functionality.