Office 365 (Outlook 2013 / 2016 / 2019 for Win) - Mark Calendar Events as Private
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.
1. Right-click on the appointment or meeting.
2. Select Private
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