An Office activator is a tool designed to activate Microsoft Office products without requiring a valid license key. It bypasses the activation process by modifying certain files or settings in the software, allowing users to access the full features of Office applications like Word, Excel, and PowerPoint. Most activators use KMS (Key Management Service) technology to achieve this, simulating the server response that confirms the product is activated. However, using such tools can violate Microsoft’s terms of service and pose risks to your system.