Create user and assign Microsoft Dynamics 365 (online) security roles

You use the Office 365 admin center to create user accounts for every user who needs access to Dynamics 365 (online). The user account registers the user with Microsoft Online Services environment. In addition to registration with the online service, the user account must be assigned a license in order for the user to have access to the service. Note that when you assign a user the global administrator or the service administrator role in the Microsoft Online Services environment, it automatically assigns the user the System Administrator security role in Microsoft Dynamics 365. More information: Differences between the Microsoft Online services environment administrative roles and Dynamics 365 (online) security roles