Classification
The six yogas are a synthesis or collection of the completion stage practices of several tantras. In the Kagyu traditions by which the six yogas were first brought to Tibet, abhiṣeka into at least one anuttarayoga tantra system (generally Cakrasaṃvara and/or Vajrayogini/Vajravarāhi) and practice of its utpatti-krama are the bases for practice of the six yogas; there is no particular empowerment for the six yogas themselves.
Read more about this topic: Six Yogas Of Naropa