How to use your Xiaomi Mi Max 3 as a remote controller for your TV
If you are one of those who never knows where the remote control has left off, there is an application that allows you to turn your smartphone into a controller for any Android TV device. The application is called Android TV Remote Control, and the only thing you will need is to have both devices connected to the same WiFi.
When you run the application, after asking for some permissions you will go to a screen where you will see the name of your Mi Box and any other compatible Android TV device that is within reach of the mobile. After clicking on the name of the device, the app will ask you to enter a code that will appear on the TV screen where you have the Mi Box connected. Enter it and that's it, the mobile will be synchronized and now it will show you a remote control interface.