Configuring Office 365 on iPhone/iPad
Open the device, and then tap the Settings application.
From the Settings menu, tap Mail, Contacts, Calendars.
Specify email type: click Exchange or maybe listed as Microsoft Exchange. **Note: If you have an old account configured in your device, remove it before adding the new service.
Enter your email address and password, and then tap Next.
Enter Exchange Server Information
Domain: <user's domain> (i.e. user's email address is email@example.com, use domain.com)
Tap Next to verify settings.
Please wait, while your device verifies the server settings. If this steps fails double check server settings, retype password and try again. Tap Save to continue.