If you don’t see the calendar list on the left, choose View > Show Calendar List.
Click Share With, then enter the names or email addresses of people you want to invite to share your calendar.
You can also enter the name of a list in Contacts to invite all the list members.
If you don’t see Share With, click below the last name or email address in the Shared With list. If you see a Shared By [name] list instead of a Shared With list, only the person named can add people.
To keep someone from making changes to your shared calendar, place the pointer over the person’s name or email address in the Shared With list, click the down arrow .
Click Shared With.
Place the pointer over the person’s name or email address in the Shared With list, click the down arrow Receive updates to shared calendars on iCloud.com.