‘Hare Ram’ sankirtan is described in the Vedas. Other sankirtans have been composed and revealed by Saints and some have been written by ordinary worldly people.
This ‘Hare Ram, Hare Ram’ is a mantra of an Upanishad. There is an Upanishad called ‘Kalisantarnopnishad’. This Ved mantra has been revealed for the souls of kaliyug. All the Ved mantras in the Upanishads have particular and very distinct vocalics and rules. However, in the Hare Ram mantra, there is no formality or protocol. The Vedas have given this freedom. You could be in the most unpleasant environment and in the most unfavorable situation and keep chanting this mantra. There is no such strict rule where one would have to first take a bath or face the east in order to chant Hare Ram.
There are three words in this mantra – Hari, Ram and Krishna. What does ‘Hari’ mean? It means the one whose Divine beauty entices and captivates the hearts of paramhans. Vishnu, Ram and Krishna all entice and captivate the hearts of paramhans. Whatever is the meaning of the name Hari, the same is the meaning of the names Ram and Krishna. Likewise, whatever is the meaning of the name Krishna, the same is the meaning of the names Hari and Ram. Many scriptures describe that the names Ram and Krishna have the same meaning. For this reason, one should be careful to not allow any kind of doubt creep into the mind (about the absolute oneness and greatness of the various forms of God) and along with that, everywhere, all the time and in every situation, anyone has the freedom to do jap or chant ‘Hare Ram’ mantra.
Thus, God has infinite names and they all have the same meaning. For this very reason, whether anyone is a worshipper of Lord Vishnu, a worshipper of Lord Ram, a worshipper of Lord Krishna or a worshipper of another descension, this mantra can be chanted for all the forms of God.