For instance, when I hold down the home button on the Galaxy S4 on the lower left side of the screen is the option to select "Task Manager". When I tap on it, it brings me to a new screen where there are tabs Active Apps/Downloads/RAM/Clear Default/Storage. When I choose RAM and tap the "CLEAR MEMORY" , it clears inactive background processes. Cleaning the memory will end some applications.
ON the note 5 tap the former menu key, to the left of home button. This shows recents, but doesn't mean the apps are open. You can clear individual by tapping x, or swiping to the right.
Every time I purchased a new phone, one of the first things I install outside of a virus scanner is Clean Master from Google Play.
Clean Master removes junk files, boosts the phone, has a cpu temperature monitor, and an app manager.
They have even wrote a anti-virus app and if you download it, it will integrate right into Clean Master for one stop service.