Hacking involves gaining unauthorized access to a computer system without malicious intent. There are different types of hackers including white hat hackers who find security vulnerabilities ethically, grey hat hackers who sometimes violate laws, and black hat hackers who hack with malicious intent. Common types of hacking include website, network, email, and password hacking. To prevent hacking, people should scan devices for malware, use strong passwords, and avoid sharing login information. Hacking can be used for both good and bad purposes.