Spyware is typically installed on a device through deceptive methods, such as bundled software or exploiting known vulnerabilities. Its primary purpose is to monitor user activity, collect sensitive information like passwords and personal data, and send this data back to the attacker. Spyware can severely compromise user privacy and security, often operating stealthily in the background, making it difficult for users to detect its presence. Common forms of spyware include keyloggers, adware, and tracking cookies.