How can I view the mobile data usage for each application for a given day? How can I view the mobile data usage for each application for a given day?



I use Android 9 on Samsung Galaxy S9.
You can achieve that using a third-party data usage application like 3G Watchdog

With 3G Watchdog you can have finer breakdown of data usage down to individuals application with options to view data usage per period including real time, day, week or month.