You can easily install apps from Google Play Store. But what if you want to install a app that is not listed on play store. Google do not accept some apps. So they are not listed on play store. But these apps are available on other websites. You can install these apps in your android phone. Android does not allow you to install these apps directly. To install these apps you need to make small changes in your Android setting.
Go to Settings -> Security-> Here you will find the option to allow installation of apps from unknown sources. Just enable thus option and you are good to go.
