The first step is to navigate to the calendar you wish to share.
Bring up the menu and tap the calendar you wish to share.
Press the ‘Invitations’ button to view all the people that have been invited to this calendar.
Tap ‘Send New Invitation’ to invite another person to this calendar. You can also swipe left-right across an existing invitation to remove a persons calendar access.
Enter the email address of the person who you are sharing with.
Choose the access level you wish to give.
Press ‘invite’ to email the invitation!