Apps use two kinds of memory: storage memory and RAM. Apps use storage memory for themselves and any files, settings, and other data they use. They also use RAM when they are running.
Go to
Settings
.
Touch
Apps & notifications
.
Touch
See all XX apps
to view all apps on the device.
Touch
Show system
to include system processes in the list.
Touch an app, process, or service in the list to open a screen with details about it and, depending on the item, to change its settings, permissions, notifications and to force stop or uninstall it.