How to sync a calendar from your Mac computer to an iPhone, to access calendar updates on both devices - Business Insider

You can sync a calendar from your Mac computer to your iPhone, so any calendar updates are reflected on both devices. There are two different ways to sync a calendar from your Mac to your iPhone - through iCloud or iTunes. ....
https://www.businessinsider.com/how-to-sync-calendar-from-mac-to-iphone