Content from Share your calendar in Outlook – Outlook (microsoft.com)

From Microsoft Outlook:

Share your calendar

  1. Select Calendar > Share Calendar.
  2. Choose a calendar to share.
  3. Select Add, decide who to share your calendar with, and select Add.
  4. Select OK and you’ll see the added people with a default permission level.
  5. Choose a name, select the access level to give, and select OK.

Open a shared calendar

  1. Open an email with a shared calendar and select Accept.
  2. Select Calendar > Shared Calendars to view a shared calendar.
  3. Choose a calendar to open.
  4. Select View in Overlay Mode to layer the shared calendar over your own.