Global administrators in Office 365 can assign users the SharePoint administrator role for help with administering SharePoint Online. The global admin already has all the permissions of a SharePoint admin. When you purchase Office 365, a team site is automatically created, and the global admin is set as the primary site collection administrator.
Users assigned the SharePoint admin role have access to the SharePoint admin center and can create and manage site collections, designate site collection administrators, manage user profiles, and more. Global admins and SharePoint admins don't have automatic access to all sites and each user's OneDrive, but they can give themselves access to any site or OneDrive. They can also use Microsoft PowerShell to manage SharePoint and OneDrive. See more about this role's key tasks below.
Site collection administrators are users that have permission to manage a site collection. They don't need to have an admin role in Office 365, and don't have access to the SharePoint admin center. A site collection can have several administrators, but must have one and only one primary administrator.
Global admins, SharePoint admins, and site collection admins all need to be assigned a SharePoint Online license.
There is a separate role called the term store administrator. Users assigned this role can add or change terms in the term store (a directory of common terms you want to use across your organization). To learn more, see Assign roles and permissions to manage term sets.
Key tasks of the SharePoint administrator
Here are some of the key tasks users can do when they are assigned to the SharePoint admin role:
Tip: When you assign someone the SharePoint admin role, you may also want to assign them to "Service administrator" role. This way they can see important information in the Office 365 admin center, such as the health of the SharePoint Online service, and change and release notifications.