Mantra is an ancient way to program your mind and manifest changes in reality. It can be song or sentence, or just a word with a deeper meaning. By repeating mantra you are tuning your mind to this vibration and reprogramming your subconsciousness.
Actually you can hear modern mantras every day. Even a silly commercial can work as a mantra for you if you hear it long enough. You don’t even have to believe in this message, if your subconsciousness receives the message for at least forty days, it takes it as granted. So you can choose your own mantras or pick up songs with positive messages that work for You and repeat them every day.