MSI (Microsoft Installer) is a Windows technology used to install, update, and repair software applications. It manages the setup process by packaging all necessary files, configuration settings, and instructions into a single MSI file. This system ensures that software installations are consistent, reliable, and easy to manage or remove. MSI files also support automated and silent installations, making them popular in business environments for deploying software across many computers. By using MSI, users and administrators can efficiently handle software lifecycle tasks while reducing errors and conflicts.