Hi, I'm very new to arduino and programing, but I have an idea that i want to set in action. But i have som questions.
What do i need to do in order for my android app to send information to the arduino?
should it go over wifi?
Looking forward to all your help.
You are unlikely to get help with Android programming here.
You ask "should it go over WiFi" without telling us what options are available on your Android device.
Bluetooth would be a lot simpler. Whether you use Bluetooth or WiFi you will need an add-on for your Arduino - a Bluetooth module. a WiFi shield or an ESP8266 Wifi module.
Bluetooth is essentially serial-by-wireless and the examples in Serial Input Basics will probably be useful.
I don't have experience of using WiFi with an Arduino.
...R