APK stands for Android Package Kit or Android Application Package. It is a file format that Android utilizes to distribute and install applications. An APK has all the components necessary for Android users to install an app onto their smartphone.
The process of installing an app on the phone using an APK is known as sideloading. Users can extract APKs from the Google Play store, or they can download APKs from other app stores.
Why Use an APK?
The most common reason why people use APKs is to download an app before it is available for a device. For instance, A Google app may take two to three weeks to become available for the mass market after Google has released the app. An APK allows users to get the app or an app update right away without waiting.
Sideloading enables users to install apps on their device that Google Play does not offer. However, users should be cautioned that downloading random APK files can present numerous security problems and other issues.