The MSI file format is used by the Windows Installer, a software installation and configuration service for Microsoft Windows operating systems. MSI files contain the information needed to install, maintain, and remove software on Windows systems. This information includes files to be installed, registry settings, shortcuts, and other configuration data. The format is structured as a database, allowing for transactional installations, rollbacks in case of failure, and advertisement of applications. MSI packages are commonly used for distributing software applications, updates, and patches. They provide a standardized way to manage software installations, ensuring consistency and reliability across different systems. The Windows Installer service interprets the instructions within the MSI file to perform the necessary actions for installing or uninstalling the software. MSI files can be created using various authoring tools, such as Microsoft Visual Studio, InstallShield, and WiX Toolset. They are a crucial part of the Windows software ecosystem, enabling developers to distribute and manage their applications effectively.