A file with an .apk extension (Application Package File) is nothing more than a packaged file of an application for the Android Mobile Operating System; which is compiled and packaged in a single file everything that is included in an Android application:

• AndroidManifest.xml file.
• .dex files (Dalvik Executable; files that run in the Dalvik virtual machine).
• Folder Resources.
• Folder Assets.

Understand Android application: games, players, readers or any program that is developed for this platform; in general an .apk file can contain any name but must have the .apk extension.

This format is used to distribute and install applications for the Android platform.

An APK is the installer on Android devices, which is used to distribute and install Android applications; that is to say, it is the equivalent of the ext of Windows but in Android. These executables contain the compiled code provided by a solution with Android Studio; This tablet includes the application code, and other associated resources such as images and, in general, any other information necessary for the application to work. APK files can be downloaded from Google Play, which is Google's Android application store par excellence, but they can be distributed in other stores or from websites; In any case, it is important to be careful when downloading APK files as they may contain malware or viruses, especially from third-party sites.