This procedure is applicable for iOS devices (iPhone, iPad, etc.) running iOS 11 and higher. The screenshots shown below were taken from an iPhone 7 running iOS 11.0.1. Other devices will be similar.
If you have iOS 11 and experience issues with email connectivity please update to the latest version of iOS 11. Apple has acknowledged an issue with the Mail app and email connectivity affecting Exchange in the following article: https://support.apple.com/en-us/HT208136
Prior to starting this procedure, authenticate your account and obtain your account-specific information from the Customer Portal according to the following article:
How to Obtain Exchange Account Information
To setup an Exchange email account on an iPhone or iPad take the following steps:
1. From the Home screen tap Settings.