As the continual trend of new applications surface up, there is a constant urge to download these apps & to try them on the handset. There are a plethora of apps in the market, but still an individual once in a while wants the “.apk file” from an outside source. Thus, in such cases initially the user is not allowed to install this specific file due to the restrictions present on the device. It is a fundamental aspect of the Android OS that it doesn’t allow the installation of applications from unknown sources i.e. most widely known as third party applications.
In such instances the application to be installed might be of significant importance to the user or for the current state of the situation. It is easy understanding the market is the easiest source of downloading apps, considering it’s on the main screen & a variety of apps are dished out for the user’s choices, however sometimes there might be a state when the user wants to install a app which is present outside the market. For example- apps that are modified in some way to avail full function.