Padmasambhava, also called Guru Rinpoche, came to Tibet from India in the 8th century and helped establish a pure lineage which is still practiced today by all four major schools of Tibetan Buddhism around the world.

The Vajra Guru Mantra, mantra of Padmasambhava’s holy name, as explained in A Treasure Text revealed by Tulku Karma Lingpa:

“… it is the life-essence of the deities of the four classes of tantra, the nine vehicles, the 84,000 aspects of the Dharma, and so on. The heart essence of all the Buddhas of the three times, the lamas, deities, dakinis, Dharma protectors, and the like is encompassed by this mantra.

Lama Zopa Rinpoche explains the following way to visualize while chanting the mantra:

“You make request to Padmasambhava and rainfalls of numberless Padmasambhava absorb to yourself and all sentient beings, and you and all sentient beings in the world generate refuge, faith in Buddha, Dharma, and Sangha and regret negative karma, from there all the realizations up to enlightenment, renunciation, bodhichitta, right view. You can think that when you are chanting…”

Some of the benefits of the mantra explained by Guru Padmasambhava himself in answer to a question from Khandro Yeshe Tsogyal:

“this essential Vajra Guru mantra — if recited with vast bodhicitta aspiration...—by ngakpas with unbroken samaya, vow-holding monastics, faithful men, women of fine qualities, and the like, however many times—one hundred, one thousand, ten thousand, one hundred thousand, ten million, one hundred million, etc.— will bring inconceivable benefits and powers.

“Countries everywhere will be protected from all plague, famine, warfare, armed violence, poor harvests, bad omens and evil spells. Rain will fall on time, harvests and livestock will be excellent, and lands will prosper. In this life, future lives, and on the pathways of the bardo, fortunate practitioners will meet me again and again—at best in actuality, or else in visions, and at the very least in dreams.

See here for more benefits and meaning of the mantra.

1 page, 2021 edition.