Answer in Details
However, sometimes mantras are extended with additional words or names (suffixes) for more specific intentions or rituals, but it is not mandatory for everyone. If your intention is pure and your devotion is strong, chanting the basic form "Om Haum Jom Saha" is sufficient and auspicious in Shiva worship.
Always remember, in Lord Shiva's philosophy, the sincerity of the heart and the focus of the mind are more important than the complexity of the mantra.