Basic Information Concerning APK Applications. Mac, Windows or Android are the typical operating systems installed on smart phones which have popular currently. Android is the most preferred app by smart phone users. The availability of Android as an open source platform has enabled many mobile manufacturers to install it on their gadgets. This has made the cost of the devices less than making their operating system or using one that is paid. Android apps are the most popular as compared to other applications that are being developed today. Each of the application when complete can carry different files and folders. The files and folders define the capabilities of the app. An archive that has all the essentials need to be built before one can operate the app on a mobile phone. The archived file become known as android package kit (apk). All the data and files that are required to run an app on a cell phone device are contained in an APK package. The package kit has a code that determines its capabilities and functions. Classes.index is the technical term for the source code. The APK also comprises of the manifest file. The component provides specifications for permission to the application’s needs, package, it’s flow, signatures, certificates, version codes and SHA-1 Digest. The other component is referred to as libs. Lib is a directory that stores information for the application through jar files or codes. The asset component has a directory that files texts, fonts and audio. The resources component is the element which defines the layout for the various pages of the app. The kit also contains res and META-INF directories. Development of an app requires that it is tested before release into the market. A secret key code is then used to sign in the application. The purpose for that is to enhance authenticity. Users can then access the app in the Google play store after it is uploaded. The android package kit is the one that gets fitted to the mobile gadget when one downloads the app. Aside from the Google play store, the other platform that offers android applications for free without requiring an account is the APK MIRROR. APK MIRROR is a website where one is allowed to download applications that are available in the Google play store. It, however, does not require one to have an account. During uploading and downloading of applications, high-security measures are provided so as to provide highly trusted and original apps to the users in the play store. The High-security measures include signature authorization and verification of certificates. APK MIRROR offers the ability to download older versions of an app if one is not satisfied with new one.