How to set up my Exchange Online email account on an iPhone/iPad?
Follow the steps below to remove your Exchange account with your iPhone, iPad:
  1. Select Settings
  2. Select Mail, Contacts, Calendars
  3. Select your Exchange account (your @ust.hk account)
  4. Select Delete Account

Setup an Exchange account with your iOS mail app

  1. Select Settings
  2. Select Passwords and Accounts
  3. Select Add account
  4. Select Exchange
  5. Sign in your email address and your password
  6. Follow the intuitive instructions to complete the remaining steps and save the settings for Contacts, Calendars, etc.