1. Open Microsoft Outlook, click the calendar that located at bottom left panel.
2. Share My Calendar locate difference between Microsoft Outlook 2007 and Microsoft Outlook 2010/2013
Microsoft Outlook 2010/2013/2016/2019
On Home tab, select the button for Share Calendar
Microsoft Outlook 2007
Share My Calendar… in Outlook 2007 locate at left panel under Other Calendars
3. After click share Calendar/Share My Calendar…
This will open an email invitation that you can send to the person you would like to share your calendar with.
4. From here, you may select the details visibility of your calendar such as Availability Only which will only show when you are free/busy. Or, Full Details which will show them whatever details you have placed into a message.
5. After clicking send the recipient will receive an email to accept and will then be able to view your Calendar.