As per Shastra’s :

।। रुद्राक्षम द्वादशास्यम यः कंठ देशे तु धारयेत आदित्यस्तुष्यतेनित्यं द्वादशास्ये व्यवस्थितः नैव वहनेर्भयं चै न च व्याधिः प्रवर्तते अर्थलाभं सुखं भुक्ता ईश्वरो न दरिद्रता ।।
पद्म पुराण, अ. ५७, श्लो. ८०/८२

Wearing 12 Mukhi Rudraksha satisfies Lord Aditya (Sun). The wearer is free from disease; he also gets wealth and happiness.

Padma Purana, Chapter. 57, Shloka. 80/82

Essence of Twelve Mukhi Rudraksha:

The 12 Mukhi Rudraksha is blessed by the Sun also addressed as Surya. Dwadash Aditya is the name given to the 12 Mukhi Rudraksha. The Padma Puran mentions that the wearer of the 12 Mukhi can acquire wealth and happiness. He is freed from the fear of fiery energies and diseases. Poverty stays away from the wearer. Any sin incurred on account of killing or abetting the murder of animals and soldiers at war is nullified by this bead.

The Shrimad Devi Bhagwatam clearly states that the wearer of the 12 Mukhi Rudraksha does not experience any fear of armed men, horned animals and lions. He is free of any physical or mental agony. Thereby this Rudraksha makes the wearer fearless and frees him from troubles. As per the Rudraksha Jabalo Upanishad, Lord Vishnu also blesses this bead. It provides leadership qualities and the individual can harness control over people. It makes the wearer radiant like the Sun and gives inner strength to govern like a mighty ruler. It eliminates all internal doubts that plague the mind and blesses the person with internal happiness.