If this is the first e-mail account on this iPhone, iPad, or iTouch, tap Mail. Otherwise, tap Settings > Mail, Contacts, Calendars > Add Account.
Tap Microsoft Exchange.
Tap in the E-mail box and enter your full e-mail address (for example, firstname.lastname@example.org).
Tap in the Username box and enter your full e-mail address again.
Tap in the Password box and enter your password.
Optionally, tap in the Description box and enter a short description for the account.
Tap Next on the upper right corner of the screen.
Tap in the Server box and enter your Exchange ActiveSync server name and then tap Next. This is the server name you found in Step1.
Choose the type of information you want to synchronize. By default, Mail, Calendar, and Contacts are all turned on. To turn off synchronization for a type of information, tap and slide the switch to OFF.