System Monitor is a system tool in Linux that allows user to view and control the processes running on their system. It provides summary of the resource usage on your system, including memory and CPU allocation.
By default, it is not installed in Elementary OS (Juno).
To install system monitor, open the terminal and run the following command:
sudo apt-get install gnome-system-monitor
After successful installation, to open System Monitor, go to
Application Menu and type System Monitor