This is a grey area: junkware is not malicious but can be extremely annoying. It is often pre-installed on a machine, but not necesseraly: you can also download junkware, often on the side of a program that you really wanted. Some of these programs are actually being used by people, in that case we can not call it junkware, but most often junkware just sits on your device, takes up space and memory and can sometimes be very annoyingly asking you to update it while yo do not use it. There are some free junkware removal-tools to be found online.