A .INI file (Initialization File) is a plain text file used by applications on Windows and other systems to store configuration settings and initialization parameters. It organizes data into sections and keys, making it easy for programs to load preferences, startup settings, and localization data without hardcoding them. INI files are simple, human-readable, and were historically very common before the rise of formats like XML and JSON. Many legacy applications and system components still rely on the .INI format for quick and accessible configuration storage.