Processes running on a computer (visible within Task Manager window) represent all the applications that are active.
Sometimes, however, some programs might launch several processes or some threads are consuming too much RAM or CPU, and they need to be ended.
Process managers will allow users to safely explore all the running threads and sort them, so that they can stop the unnecessary ones.
However, this should only be performed by computer experts because there are several processed that are required by the OS to function properly.