If you want to install Android apps on your mobile you must download from Google play store. Android Injector is software that will allows you to install Android apps from your computer via USB connection.
You can simply install this software. You must have USB Debugging mode enabled, and the proper drivers installed. You can download apps from anywhere onto your computer then install them on your phone via USB connection.
Just install the USB drivers for your phone or device onto your computer connect your phone to your computer via a USB cable, select any amount of Android app files (.apk) and click “Install to device”. No need to root your device or any of that complicated stuff.