About the Exchange Online admin role
To help you administer Office 365, you can assign users permissions to manage your organization's email and mailboxes from the Exchange admin center. You do this by assigning them to the Exchange admin role.
Tip: When you assign someone to the Exchange admin role, also assign them to the Service admin role. This way they can see important information in the Office 365 admin center, such as the health of the Exchange Online service, and change and release notifications.
Here are some of the key tasks users can do when they are assigned to the Exchange admin role:
Set up mailbox features such as the mailbox sharing policy: how users can share calendar and contacts information with others outside of your organization.
Create a shared mailbox so a group of people can monitor and send email from a common email address.
Office 365 email anti-spam protection and malware filters for the organization.
Manage Office 365 Groups
Exchange Online role groups
If you have a large organization, the Exchange admin might want to assign users to Exchange role groups. When an admin adds a user to a role group, the user gets permissions to perform certain business functions only members of that group can do.
For example, the Exchange admin might assign someone to the Discovery Management role group so they can perform searches of mailboxes for data that meets certain criteria. To learn more, see Permissions in Exchange Online and Manage Role Groups.