Why Mahashivratri Is Celebrated 

Maha Shivratri, as the name suggests, is a day dedicated to Lord Shiva.
Shivaratri, it is said, is the convergence of Shiva and Shakti — the masculine and feminine energies which balance the world.
In the south, chaturdashi tithi during Krishna Paksha in the month of Magha, is known as ‘Maha Shivaratri’, as per the north Indian calendar, Masik Shivaratri in the month of Phalguna is known as Maha Shivaratri. 

Date : 11th March, 2021
Chaturdashi Tithi Begins - 02:39 PM on Mar 11, 2021
Chaturdashi Tithi Ends - 03:02 PM on Mar 12, 2021 
Maha Shivaratri is observed by remembering Lord Shiva and chanting mantras
Like Om Namah Shivaya (ओम नमः शिवाय)
prayers, and fasting, jaagran . Devotees 
Offerings fruits, leaves (बेल पत्र ), sweets and milk to Lord Shiva. 

Mahashivratri – A Night of Awakening 

Shivratri, which is the darkest night of the month, it is an opportunity for one to dissolve their limitedness, to experience the unboundedness of the source of creation which is the seed in every human being. So, Mahashivratri is an opportunity or a Night of awakening for you.