Advice for Tax identification number


I am non-us author, i got an email from envato stating that, as a non-us author i have to fill this Form W-8 form. But there is a column “Tax ID Number”. . I am from india (individual), and i don’t know which one option is appropriate for me and where i can get it.

Kindly help me with it.

See this thread: INDIAN Authors - USA(iTin) Tax Discussion Only