Marking a meeting or appointment private can hide some of the meeting details from others in your organization.
Important: If you share your Calendar, Contacts, or Tasks folders with one or more people who have Read permissions, the Private feature will not prevent them from seeing the details of your appointments. In addition, anyone with Read access to your folders could use programmatic methods or other email applications to view the details of your private items.
Sharing your folders and assigning Read permissions must be done explicitly. To share a folder, see Share an Outlook calendar with other people.
Create or open the appointment or meeting that you want to make private.
On the Meeting or Appointment tab, click Private.
Save or send your meeting or appointment as usual. Any meeting attendees will be able to see the details of the meeting.