You can set up holidays from [Settings] -> [Edit Calendars] -> [Holidays].
1. Use country search to select the appropriate holiday calendar.
2. Subscribe to the holiday calendar.
Tap the [Subscribe] button.
3.Tap the [Done] button to add the holiday calendar.
※ Please note that if you tap the [View Event] button, you will go to iCal.
※ You can delete the holiday calendar from [Settings] on your iPad.