There are two slightly different ways to do this and they are outlined below.
Getting Office 365 up and running on your iPhone
Go to Settings – Mail – Accounts - Add Account
Select Microsoft Exchange as shown in shot 1,
Then just enter your username and password and it’s done.
Setting up an Exchange server outlook email (in-house email) with an iPhone
If you don’t have Office 365 don’t worry, you can still get you exchange email on your iPHoneHowever, we do recommend moving to Office 365, as it is a great service.
Go to Settings - Mail – Accounts - Add Account
Select Microsoft Exchange
Enter email address and password
Next – Continue
Enter Server e.g. mail.bytek.ie (Contact Bytek if you don’t know this)
Enter Username (Your PC login username)
Enter Password (Your PC login password)
Then hit done and use your mail
If this doesn’t work contact firstname.lastname@example.org