Question

why does a compass needle always point towards north direction

Answer 1

due to the Earth's magnetic field

Answer 2

The Earth is a magnet that can interact with other magnets in this way, so the north end of a compass magnet is drawn to align with the Earth's magnetic field. Because the Earth's magnetic North Pole attracts the "north" ends of other magnets, it is technically the "South Pole" of our planet's magnetic field.