If you schedule meetings using the Microsoft Outlook calendar, but you need to invite participants who only use Gmail, you can format invitations for the Gmail calendar using options in Outlook. Outlook uses the vCalendar file format for invitations, but the Gmail calendar uses the iCalendar, or “iCal,” format. You can forward a single invitation in the iCal format from Outlook, or you can change the settings in Outlook to send multiple invitations in the iCal format.
When the Gmail recipient receives the invitation, she simply clicks on the iCal file to accept the meeting and automatically enter the information in her calendar.
The issue occurs when the Mac Calendar won't sync with Exchange and then. (Would it have to do with the fact that there were calendar invites in my mailbox?). Seems to work ok on my iPhone and on another Mac with OSX Sierra. How to Send a Calendar Invite on Outlook on PC or Mac. This wikiHow teaches you how to create a new calendar event on Microsoft Outlook and send an invitation message to your contacts, using a desktop computer. Open Microsoft Outlook on.