You can easily keep tabs on what’s running on your Mac and get things running smoothly by using Apple’s Activity Monitor. Here’s how to get started.
Most applications running on UNIX-based systems are called processes, and since macOS is based on UNIX, it is no different. Apple’s Activity Monitor app allows you to look at, monitor, and stop most macOS processes running on your Mac.
Activity Monitor ships with macOS and lives in /Applications/Utilities. To run it, double-click it from the Finder in the Utilities folder.
Read more at AppleInsider.com