This Mantra is composed of three Sanskrit names of the Supreme Being; “Hare”, “Krishna” and “Rama”

Hare Krishna Hare Krishna Krishna Krishna Hare Hare
Hare Rama Hare Rama Rama Rama Hare Hare

हरे कृष्ण हरे कृष्ण , कृष्ण कृष्ण हरे हरे |
हरे राम हरे राम , राम राम हरे हरे ||

Meaning

The Hare Krishna mantra, also referred to reverentially as the Maha Mantra “Great Mantra”. This Mantra is composed of three Sanskrit names of the Supreme Being; “Hare,” “Krishna,” and “Rama.

Understanding

The three words— Hare, Krishna, and Rama—are the seed sounds of the maha-mantra, Hare refers to the energy of that One Infinite Source of all of us. The energy thats present all around us.
Rama and Krishna refer to incarnations of Lord Vishnu.
When Chanting this Mantra, we are calling for that universal energy. This Mantra has the power to dissolve our bad habits and negative emotions. By chanting or listening to the Mantra, you become free from all anxiety and inner fears.

Benefits of Chanting Hare Krishna Maha Mantra

1. Dissolves bad habits, evil thoughts & Negative emotions,
2. Get rid of fear, stress and anxiety
3. Helps to achieve big
4. It brings the highest state of ecstasy
5. It brings joy, peace and happiness
6. It relieves from all miseries
7. Gives divine qualities likes Love, mercy and inner happiness
8. It purify yourself and surrounding
9. It cleans your mind and heart
10. When you chant Hare Krishna Mantra, we start to clear the impure consciousness, that keeps us unhappy and away from our true self. This mantra in a way connects us to that higher energy and helps us to break away from that endless cycle and attachment to the physical world.

Here is a Srila Prabhupada chanting meditation of this mantra with 108 repetitions.