Reply to a calendar invitation on iCloud.com
Accept, decline, or say maybe to a calendar invitation
Do either of the following:
In the invitation email you receive for the event, click Accept, Decline, or Maybe.
In Calendar on iCloud.com, click the Show Notifications button below the calendar. If you have one or more pending invitations, the button shows a number instead of an arrow.
In the event notification, click Accept, Decline, or Maybe.
You can update your reply in the event on your calendar or in the original email invitation.
Set the default calendar for events and invitations
In Calendar on iCloud.com, click the Action pop-up menu in the bottom-left corner, then choose Preferences.
In the General pane, click the “Add events & invitations to” pop-up menu, then choose a calendar.
You can move events to a different calendar at any time.