Ask Siri. Say something like:
“Set up a meeting with Barry at 9.”
"Do I have a meeting at 10?”
"Where is my 3:30 meeting?”
Add an event. In day view, touch and hold a time until a new event appears, then fill in the event details. If you add the address of the event’s location, you’re reminded in time to leave from your current location, based on traffic conditions.
Add an event from the Home screen. On iPhone 6s and iPhone 6s Plus, press Calendar, then choose the New Event quick action.
Search for events. Tap 
, then enter text in the search field. The titles, invitees, locations, and notes for the calendars you’re viewing are searched.
Ask Siri. Say something like: “What’s on my calendar for Friday?”
View a weekly calendar. Rotate iPhone sideways.
Change your view. Tap a year, month, or day to zoom in or out on your calendar. In week or day view, pinch to zoom in or out.
Peek at a day’s events. On iPhone 6s and iPhone 6s Plus, in the monthly calendar, press a date to peek at that day’s schedule. Or, press deeper to pop open the schedule.
View a list of events. In month view, tap 
to see a day’s events. In day view, tap 
.
Ask Siri. Say something like: “What’s on my calendar for Tuesday?”
Change the color of a calendar. Tap Calendars, tap 
next to the calendar, then choose a color from the list. For some calendar accounts, such as Google, the color is set by the server.
Adjust an event. Touch and hold the event, then drag it to a new time, or adjust the grab points.
Ask Siri. Say something like: “Reschedule my appointment with Barry to next Monday at 9 a.m.”