Thanks for using Apple Support Communities.
For more information on this, take a look at:
Calendar: Share iCloud calendars
Select how you want to share the calendar.
If you select “Only the people you invite,” you can specify people to share the calendar. Click Add (+), type a person’s email address, and then select read-only access or read-and-write access in the Privilege column. To invite another person, click Add again.
Best of luck,