You can share your calendar with either the public permission or the private access.
To share with public permission, go to Calendar Settings >> My Calendars >> Click Share for the calendar you wish to share >> Enable Make this calendar public >> copy the public URL HTML and share it with others.
To share with private permission, go to Calendar Settings >> My Calendars >> Click Share for the calendar you wish to share >> Enable private address for this calendar >> copy the public URL HTML and share it with others.