If you didn’t allow the app to access your Apple apps (after installation), you will then need to add an account before you can use the app.
- Tap the Calendar icon (top left corner) > Settings > Accounts > Add Account.
- Choose the account you want to add from the following:

- iCloud
- Exchange
- Office 365
- Outlook.com
- Yahoo
- fruux
- Meetup
- todoist
- webex
- Zoom
- CalDAV Account
How to completely disable accounts from iOS
- Tap the calendar icon (top left corner) > Settings > Accounts.
- Tap Accounts from iOS.
- Turn off Show Calendars from iOS and Show Reminders from iOS.