As the highest reality Shiva is both Saguna (with form and qualities) and Nirguna (without form and qualities).

As the highest reality Shiva is both Saguna (with form and qualities) and Nirguna (without form and qualities). ShivaLingam is a rendering of Shiva in his formless or nirguna aspect. Saguna Shiva is known by his five aspects known as panchanana aspect and we can see a ShivaLingam in certain temples having five faces representing these five aspects. However, Nirguna Shiva is the highest reality, the absolute principle, the formless unknown Self of all and the one indivisible Supreme Reality. ShivaLingam represents this aspect of Shiva and therefore its worship is considered to be the highest form of worship we can perform.

According to the Shiva Maha Purana, in Kaliyuga, worship of ShivaLingam is the best means of liberation. Worship of ShivaLingam can be done either at home or in a Shiva temple with all sixteen rituals along with chanting of Puranic Mantras in month of Shravan. Worshiping Lingam with all sixteen rituals is known as Shodashopachara Puja.

dhyana ( meditate on shiva)
avahana ( invite him to your home)
asana (request him to sit)
padya ( giving water to wash his feet)
arghya (giving water to wash his hands)
achamaniya (give him Ganga Jal)
Godugdha (bath with cow milk)
Dadhi snanam ( bath with curd)
Ghrita ( bath with ghee)
Madhu ( bath with honey)
Sharkara (bath with sugar)
Shuddodaka (pouring water on lingam)
vastra ( adorning him with cloths)
bhasma (applying bhasma)
gandha (applying sandalwood )
akshata (sprinkling rice)
pushpa (praying with flowers)
bilva (offer bilva leaves)
dhupam (lightening the agarbathi)
Deepam (lightening the Deepak)
naivedyam ( offering food to shiva)
tambula (offering betel leaf, nuts)
Dakshinam ( praying to Shiva by offering money)
Aarti ( offering aarti with lit camphor)
Pradakshinam (take half parikrama of shiva)
mantrapushpa (repeat mantra and offer him)
Kshama prarthana or namaskara ( pray folding both your hands)
prardhana (make your requests to Shiva for his blessings to grant your wishes)

Om Namah Shivaya ~🙏🏻🙏🏻