Today Microsoft has announced an app update for those Office 365 administrators who are constantly on the go and don't have time to setup a laptop or workstation to address tasks. Office 365 admin app is available for Windows Phone, Android, and shortly, iOS 8.
Initial functionality includes:
Adding, editing or deleting users
Reviewing service health
Active service requests
For Windows Phone 8.1, download the app from the Windows Phone Store.
For Android 4.0+, download the app from Google Play.
The iOS 8 update will available soon, but for now you can download the current version Apple App Store.