1. Is there any form to the soul and supersoul?

The supersoul has a four-armed form. The individual soul has a latent form, which relates to its spiritual form.

2. Does water have some form. (It has a spiritual form like Varun Dev). But what about in material world. It is in liquid state. Is there any other form that we can define. Because Krishna is having personal form so His energies also must have some form. 

The element water has no specific form, it has the quality of taste. Form comes with fire, smell comes with earth, and touch comes with air. But on another level, there can be a deity or form of the water, which depends where you take the water from. Ganga-jala is presided over by Ganga-devi, for example.

3. Why should we read the scripture in actual sense. What would we gain by doing this?

We study scripture to establish paramarthika-sraddha and relationship with Hari, Guru, and Vaisnavas. We receive transcendental knowledge through scripture. The Srimad-Bhagavatam teaches that the people in Kali-yuga, their minds and memory are not very sharp, so for the benefit of the people, Vedavyasa gave the teachings of the Supreme Lord in the written form of scripture. Without hearing the pastimes of the Lord, there is no auspiciousness for the jivas. It is only by hearing that we can progress. Sravanam is the first limb of navadha-bhakti. Reading is there to help us remember what we’ve heard.

4. Why do Krsna and His incarnations appear only in India but not outside India? The world is so huge, still Krsna and Visnu appeared and many of the demigods also selected India as their only place of worship and practice sadhana of their spiritual life. What is the reason behind this?

The whole world we see now is part of Bharata-vesa. Specifically, now, it means India. All the tirthas etc. are in India. It is only by great sukrti to appear here. Before it was Mahabharat, now it is just Bharata. It is the most pious land on Earth. Everything is not equal. So Bharata or specifically India, is the best of lands, therefore He appears here. But the Lord also appears in Svarga, as Vamanadeva.