Yoga provides us with a technique to unload ourselves from the conditioning that we have acquired during this life. As Carl Jung quote which I love is: “Until you make the unconscious conscious, it will direct your life and you will call it fate”. Yoga is a way to remove the “software” which has been installed in us, allowing us to become more like our intrinsic nature, or “hardware”. When we liberate ourselves from conditioning, we are able to exercise more free will.
In the second yoga sūtra of Patañjali is said that yogaś citta-vṛtti-nirodhaḥ – yoga is the inhibition of modifications of the mind. By redirecting the focus from outside to the world within, we become aware of the pure consciousness which is our essence. It is so much more than the mind & body that we experience.
Yoga does not add anything, it removes what stands between you and your true nature!