How does Apple's mobile calendar stop advertising messages?

Recently, many Apple users are complaining that the iPhone calendar is suddenly full of advertisements, and all kinds of garbage can't be prevented. Many users don't know how Apple's mobile calendar blocks advertising information.

First, delete the calendar reminder.

Open the calendar App, click "Calendar" at the bottom to enter the subscription page, click the exclamation mark behind the personal/work calendar, close the "Schedule Reminder" and delete the calendar.

Second, cancel the iCloud calendar synchronization.

Open the settings, click on your Apple ID account, then enter the iCloud page, find the calendar option, and turn off the calendar iCloud synchronization switch.

After the above two steps, I believe I won't receive calendar advertising messages again.