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APK (Android Package Format) is the package file format used by the Android operating system for distribution and installation of mobile apps and middleware.
If you want to install an app/game on Android, you need the APK files, which can usually be downloaded at Playstore. Basically APK files is like EXE files in Windows.
There are many Android Apps out there so there are many APK files. I will give you one for example.
Sunshine Top brand IPTV APK HDFlix download address:
Download this apk to your android system to enjoy 1500+ worldwide channels and 1000hours VOD movies.