You can add and update calendar events directly on iPad.
Add an event: Tap and enter event information, then tap Done.
You can also touch and hold to add a new event to an empty spot on a calendar. Drag the grab
points to adjust the event’s duration.
Set an alert
Tap Alert, then set an alert for 5 minutes to two days before the event.
Set a default alert for events
Go to Settings > Mail, Contacts, Calendar > Default Alert Times.
Update an event
Tap Edit, then change event information.
To adjust an event’s time or duration, touch and hold the event to select it.
Then drag it to a new time, or drag the grab points to change its duration.
Delete an event
Tap the event, tap Edit, then scroll down and tap Delete Event.
Invite others to an event
Tap Invitees to select people from Contacts. Requires an iCloud, Microsoft
Exchange, or CalDAV account.