Office 365 (Outlook 2013 / 2016 / 2019 for Win) - Calendar Sharing
you can send a sharing invitation to other users so they can view your calendar in their own Calendar list. Calendar sharing isn't limited to the default Calendar folder that is created in all Outlook profiles. You can create additional calendar folders and choose which of those folders to share. For example, you can create a calendar folder for a specific project and share it with your co-workers. Optionally, you can grant them permission to modify the events and appointments in the calendar.
1. Click Calendar. Note: Starting with Outlook 2016, icons have replaced words if you have Compact Navigation enabled. If so, click on the calendar icon on the bottom left instead.
2. Click Share Calendar.
3. For the most current information on calendar sharing, please check out the following Microsoft help article: https://support.office.com/en-us/article/Share-an-Outlook-calendar-with-other-people-353ed2c1-3ec5-449d-8c73-6931a0adab88.