Shankara taught the rules of bhakti, yoga and karma as a means to enlighten the intellect and purify the heart. He gave primary importance to Jnana yoga, or the "yoga of Knowledge," because it was usually regarded as the highest yogic path. Even Patanjali states that liberation, or Self-realization, is gained by knowledge, not by any other means. In this thinking, yoga is a way to achieve that higher knowledge.
Shankara was also a great raja yogi, and a teacher of a fifteen-fold path of Raja yoga, which was a bit different than the Raja yoga of Patanjali. Shankara's version of Raja yoga was more focused on jnana (knowledge). In some of the later works of Shankara, he describes a few concepts from Hatha yoga including kundalini, the chakras, nadis, different pranayamas, mantras and rituals.
Shankara is thought to be the author of a poem called "Yoga Taravali," wherein he poetically and metaphorically summarizes the highest teachings of yoga, explains the different stages of yoga, and outlines how to reach the highest state of Raja yoga.