KMSpico is a popular tool used to activate Microsoft products, including Windows and Office, without purchasing a license. It functions by emulating a Key Management Service (KMS) server, tricking the software into believing that it has been activated through a legitimate channel. The tool is typically easy to use; once installed, it automatically activates the Windows or Office installation on your device. However, it's important to note that using such activators can violate Microsoft's terms of service and may expose your system to security risks.