Malware is the short term for Malicious Software. This kind of software is dangerous because it can secretly access a device without the user's knowledge to steal information.
There are different types of malware; it can be in the form of adware, spyware, phishing, viruses, worms, trojan horses, ransomware, rootkits, and browser hijackers.
A sign that your computer is infected by malware is when it is running slower than usual. It also involves frequent crashes on your browser, pop-ups, and spam. To help you know if you are infected you can use malware scanner.
Just in case you get infected by malware, the best course of action is to get rid of it using a powerful and reliable malware removal tool.