1. If this is the first email account on your iPhone, tap Mail. Otherwise, tap Settings > Mail, Contacts, Calendars > Add Account.
3. Tap Microsoft Exchange.
4. You don’t need to type anything in the Domain box. Type the information requested in the Email, Username, and Password boxes. Type your full email address (For example, email@example.com) in the Email and Username boxes.
5. Tap Next on the upper-right corner of the screen. Your mail program tries to find the settings it needs to set up your account. Go to Step 8 if your mail program finds your settings.
6. If your iPhone can’t find your settings, In the Server box, type outlook.office365.com, and then tap Next.
7. Choose the type of information you want to synchronize between your account and your device, and then touch Save. By default, Mail, Contacts, and Calendar information are synchronized.
8. If you're prompted to create a passcode, tap Continue and type a numeric passcode. If you don’t set up a passcode, you can’t view your email account on your iPhone. You can set up a passcode later for your iPhone settings.