How to assign roles and permissions in Admin Center using Office 365

Log on to Microsoft Office 365 portal.
In Office 365, click on App Launcher icon, and then select Admin.
Go to “Users” and click on “Active users”.
List of all available users will appear on your screen. Select any user you want to assign permission.
When you select any user, user details are displayed on right side. If you want to assign permissions, click on “Edit”.
New window appears on your screen, click on “Settings”.
Now, click on “Additional details” to view “Roles”. You can change role from the drop-down list where we assign the “Global Administrator” role, as an example.
Under Assign permissions, click Yes or No to assign permission and select administrator role.
Fill the alternative email address in the dialog box. Click Save.
Finally, your administrator permission settings complete.