Change the Display Settings of the Reading Pane in Exchange Online

  1. Go to https://mail.office365.com.
  2. Enter your HKUPortalUID@hku.hk and PIN. Click Sign In.
  3. Click Settings setting at the top right.
  4. Choose View all Outlook settings.
  5. Go to Mail > Layout, select the preferred layout.
    change_display_pane

  6. Click Save.