PS4 Second Screen is a free solution for linking your Android smartphone to your PlayStation 4 console. There are a couple of advantages for doing this, but the first thing you need to do is to provide the credentials for your PSN account. You won't be able to access any of the features if you don't complete this vital requirement.
The application offers a very simple and direct design where you can check if the connection between your mobile device and the console is established. As you can probably expect, if everything works just fine you will be able to use your smartphone for sending commands to your PS4. If you're playing a game that has support for the second screen feature, the app will display in-game information right on your Android device.
Another key aspect of this tool is the ability to to enter text on the PS4 console by typing it on your smartphone or tablet. This feature is rather important because it's way easier to type words using the keyboard of your smartphone instead of working with the DualShock one. In order to use the features mentioned above you will have to stay connected to the Internet.