Android doesn't have its own traffic monitoring.

The ROM issued by various manufacturers and the system that comes with the mobile phone may have traffic monitoring.

But it is also equivalent to built-in software.

If your mobile phone doesn't have traffic monitoring, you can download Tencent Mobile Manager or Traffic Assistant.

There can be traffic monitoring function.

It can be downloaded from the App Store.

Then in the mobile phone settings-notification, you can notify in the notification bar.

I hope I can help you and adopt it.

Tencent Computer Manager Enterprise Platform: /c/ Manager/