When we talk about formless god it does not mean that he/she is not present there it just mean that we can’t see him just like we can’t see the atoms and molecule present in the air but that does not mean that they are not there. Similarly, we can’t see the soul but it is there and we can feel it. In sanatan dharma there are two types of science. First one is Para Vigyan and second one is Apara Vigyan. In Para Vigyan there are things which are not seen by our bodily eye like god thus to see god we need to open the eyes of our soul and Yogis are the masters of it. A yogi knows a sky elements and air elements he knows the different forms of gods. Similarly, Arjun has seen the different forms of lord Krishna in divine terms a yogi can reveal the real god and when we try to see god in a scientific way he is seen as formless.