To add a subscribed local calendar you should do the following:
- Launch the iOS Settings app.
- Go to Calendar .
- Tap Add Account .
- Tap Other .
- Tap on Add Subscribed Calendar.
- Enter the server location of the calendar. Usually, it's a web address that ends in .ics
- Tap Next and then Save .
- Launch Calendars and go to Settings.
- Go to the Local Calendars settings menu and make sure that the subscribed calendar toggle is enabled there.
Note: You can also subscribe to an .ics calendar by tapping on a link to the calendar in the email or text message.