Open the "Settings" menu on your phone and scroll down to "Passwords & Accounts"`
You will then see the accounts you have already setup, click on "Add New Account"
**If you do not have any accounts setup, you will see the next screen, shown below**
Click on "Microsoft Exchange"
Enter your email address and a description.
You will then be asked to "Sign In" or "Manually Configure" - Click sign in and you will then be prompted for your password. The rest of the settings are then personal, sync of contacts, calendars etc. Ensure that mails is "On" to recieve emails.