Why can't I add attachments to events in iCalendar anymore (iPhone XS iOS 13.3)?

Hello vickiOsf,

Welcome to the Apple Support Communities. I understand you want to add attachments to events with Calendar. I'll gladly explain what you can do.

Adding attachments is a feature of the account provider for your calendar. iCloud offers attachments with events: Attach files to a calendar event on iCloud.com

Cheers.