3 Mukhi Rudraksha is the symbol of Three Deva i.e. (Brahma, Vishnu and Mahesha). The person who wears this Rudraksha after proper Sidhhi ( method of purification & charging with Mantra) will always get the blessings of three powers and accompanied by three Deva. The wearer of this Rudraksha no longer remains an ordinary man since three power remains with the wearer always which help him to get success in all of his works. The person who wears such Rudraksha has no difference of opinion in saying, thinking and doing in practical. The Rudraksha takes all the miseries and sorrow from the life of the wearer and makes the life full of happiness and comforts.

Rules for the Rudraksha: The Wearer of the Rudraksha should chant related Rudraksha Mantra along with Rudraksha Utpatti Mantra (Mantra for the Rudraksha Origin) daily at least 9 times while wearing and removing in the night before going to sleep. More Rules ...

Note : Above details are taken from ancient handwritten text and Guru Mukha. The description is seen in the deep meditation of Lord Shiva by Lord Datta Treya.

Three Mukhi as per the various Puranas :

Three Faced Rudraksha has three natural lines. It is the symbol of god Agni ( fire ). The Agni ( fire ) purifies every thing in the same way, the wearer of 3 Faced Rudraksha gets rid of the sins that he had done in his past life and returns to the purely true life. It is the best for those who have fallen prey to inferiority complex or fear stricken and suffer from self hatred or mental strain.

In a short time after wearing it, the wearer feels its influence by attaining success in his efforts, favorable means, learning and knowledge. Its another best virtue is that it makes the wearer free from chronic fever certainly. Modern physicists and allopathic doctors accept that the patient of the fever that comes after every 3 days, is cured.

It contains the Trinity of gods Brahma and Vishnu and Mahesh and the trinity of Gunaas Sattva and Rajas and Tamas and the three spheres The Sky The Earth and The Paatal with their divine powers. For its divine powers this bead is the most sacred and powerful and the best.

3 Mukhi Rudraksha Bead is Known to be one of the most powerful Rudraksha for stopping all problems created in the past and existing in the present moment and about to take place in the Future. This Rudraksha Bead combined with appropriate Mantras helps to dramatically change a persons life for the better in the 40 days it takes to complete an initial Mantra Discipline. The 3 Mukhi Rudraksha Bead is a life saver.

In the SIVA PURANA Vidyesvara Samhita Translated by Shastri 1973

Suta said

Rudraksa is a favorite bead of Siva. It is highly sanctifying. It removes all sins by sight, contact and japas.

SIVA said

If a man is not liberated after Meditation and acquisition of Knowledge, he shall wear Rudraksha. He shall be freed from all sins and attain the highest goal. A Rudraksha of 3 Faces always bestows means of enjoyment. As a result of its power all lores become firmly established.
O daughter of king of mountains thus I have explained to you the different types of Rudraksas based on the number of faces. Please listen to the mantras with devotion

Klim...Obessiance...3 Faced Rudraksha Bead

In the PADMA PURANA Chapter 57 Translated by Bhatta 1989

THE LORD Said

The one with three mouths is Fire Himself; the sin earned in the past births of him on whom it remains is burnt as fire burns fuel. A wise man obtains that fruit which is obtained by worshipping Fire or by rites of honoring Fire or by offering the oblation of ghee; and also obtains heaven. He who wears a Rudraksa of three mouths on his body is like Brahma on the earth. It would burn all the sins due to wicked deeds collected in birth after birth. There would be not disease in his belly; he would not be
sick. He is never defeated, and his house is not burnt by fire. These and all other fruits are obtained and destructive weapons also are warded off. Nothing inauspicious happens due to wearing of Rudraksa of three mouths i.e. when a Rudraksa of three mouths is worn on one's person.

In the RUDRAKSAJABALOPANISAD

KALAGNI RUDRA replied

The one with three faces is Fire Himself, which on wearing pleases all the three Fire deities.