IPhone – Can’t create events on iPhone 6 calendar

I had this problem. I drove 75 miles to nearest Apple store with an assigned appointment time just to have the "tech" flip a setting button from "Show" to "Hide".

In other words if you press "Hide" it hides the calendar, but in pressing "Hide" it changes the button to "Show". So when I was looking at the button which says "show", I assumed it was in show mode. Silly me. You have to press show to make it actually show, but then the button will display as "Hide", as if you're in hide mode, but you're not. It's an action button. Press for Show or Press for Hide. Whatever is displayed, your phone is doing opposite to that.

The button can be found by pressing Calendars to bring up a list of your calendars, then pressing the relevant Show button for the calendar. Alternatively, you can press the Show All Calendars button to unhide all the calendars at once.

You may be inadvertently saving the event to the wrong calendar. Often email accounts, such as Gmail automatically enable a calendar when being set up. If the event shows up only on your iPhone, and nowhere else, chances are your default calendar is set to something that you are not used to checking.

When you create an event, scroll down to where you can see the menu item "Calendar". Tap that, and choose one of your iCloud calendars. If the event then shows up on iCloud, and your computer, you have chosen the correct calendar.

If this is case, you will probably want to change your default calendar by opening your Settings.app, scrolling down and selecting "Mail, Contacts, and Calendar". At the bottom of this screen is a section titled "Calendars". Change the "Default Calendar" to reflect the one that worked correctly.