Why does Apple Schedule receive yellow messages?

It is the system calendar that gives the application permission to write.

After the APP is authorized, you can add a memo to your calendar, and after the specified time, the calendar will display these push messages. I suggest you delete unnecessary apps and turn off unnecessary push.

If you are used to using Apple's own three-party calendar software, you can click Turn off calendar synchronization in Settings -iCloud to keep or delete the synchronized calendar archive. In this way, it's just that you can't see it yourself, not that you really can't receive spam. If you use your own calendar, there is a more troublesome method besides not seeing it, that is, the software deletes it manually. When you install Tencent Mobile Manager, you will see that calendar advertisements are cleaned up and spam will be automatically detected and deleted. However, due to permission issues, the mobility manager cannot retrieve and delete information.