APK has a full form Android application package.
Android Package (APK) is the package file format used by the Android operating system, and a number of other Android-based operating systems for distribution and installation of mobile apps, mobile games, and middleware.
There are also some important apps that are too MB difficult to download from the play store, on this condition we use Apk file.
Google also has some software which you can go and download that software.
After downloading, you can go to your file manager and have an Apk option in it, you can click on the software you have downloaded on your Apk file and then it will start downloading. Then you can back up and see that your software has been downloaded.
