sync outlook calendar with iphone calendar

Here is what I found on Microsoft’s web site—>https://support.office.com/en-us/article/Synchronize-Outlook-and-Apple-iPhone-or-iPod-touch-calendars-BE7A12EB-FE76-4346-AE13-B54249DB7F9C

That is an offline sync using iTunes. I also found real time sync using 3rd party apps: https://www.windowscentral.com/how-set-outlook-calendars-iphone

This assumes that your calendar is Outlook and not MS Exchange. If it’s Exchange it will sync automatically just by turning on the calendar.

Go to Settings/Passwords & Accounts, add the Outlook account, and turn on Calendar.