Step 1
On the home screen of the device, tap Calendar.
The removal process has changed in the newer versions of iOS Calendar. If you're using an older version, please take a look at calendar removal in older versions of iOS Calendar.
Go to a day which has an event from the calendar you wish to remove. It can be either an all-day event or an event occurring at a specific tine.
Tap on that event to open it.
Updated 5 Nov 2023