To set these meeting invitations, you have to configure your Calendar settings on web view by doing the following:
- Log in to the Office 365 Portal.
- Open the Calendar.
- Click the gear on the top right corner. The settings pane will pull out.
- Click IPOP and IMAP under the Accounts tab in the Options pane on the left side of the screen.
- Click Send invitations in iCalendar format under POP Options.