Like electric fields, magnetic fields have a direction. They run from the "north pole" to the "south pole" of the magnet. The direction of the field can be represented by arrows or by these moving yellow bands.
Unlike electric fields, magnetic fields don?t begin and end on charges. The basic physics says they could - but scientists have never discovered any magnetic charges ("magnetic monopoles") - even though they have looked! So magnet fields always loop back upon themselves.