The following settings are from IOS 13. Slightly newer or older versions should be very similar:

1.  Settings - Password and Accounts Screenshot
2. Add Account
3. Microsoft Exchange Screenshot
4. Email: your full email address & Description: What you want to call the account Screenshot
5. Configure Manually Screenshot
6. Enter your email password Screenshot - hint: You can test your login and password from your computer at Outlook Web Access
7. Enter the server settings Screenshot
   1. Server: exchange.corpwest.com
   2. Domain: leave empty
   3. Username: full email address
   4. Password: email password
   5. Description: What you want to call the account
8. Choose what you want to sync (default is usually OK) Screenshot
9.  Save