KMS Pico is a popular tool used for activating Microsoft products such as Windows and Office. It works by emulating a Key Management Service (KMS) server, which allows users to activate their software without requiring a genuine activation key from Microsoft. This method is often used by those who have lost their original keys or are looking for a way to bypass activation limits. However, it’s important to note that using KMS Pico for activation can violate Microsoft’s terms of service and may not be legal in all jurisdictions.