I have looked all over the place and cannot seem to find a way to automatically remove an app's respective notification upon the app opening from the app launcher. In iOS this behavior was just a given but, in Android the notifications remain even after opening the app. If I open the app from the notification, the notification is cleared out, but I may not want to open the app from the notification because it may take me to a part of the app that I don't want to go to (like directly into a particular email rather than the inbox).
I am on a Note 9 running 8.1.0. Not rooted.