Tax liability for foreigners(Question)

hi everyone there,
i want to open mini account with efx. on there account opening page i found this “Applicants residing outside of the U.S. must also submit a valid passport or visa and [U]foreign customer notification forms[/U]”

under [U]foreign customer notification forms[/U] link they r asking for
"Unless you complete either the W-8 or the W-9 sections (i.e. you fail to furnish us with the appropriate W-8 Form or with
the correct taxpayer identification number), MBTF must withhold between 30% or 31%, whichever is applicable, of the
withdrawals and payments from your account."

plz someone clarify this

efx has not live chat, and other broker’s chat pannel’s are saying that they don’t detect tax in any case.
then why efx is asking for this ?

do i have to pay the tax in broker’s country or in the country i’m residing?

I’m resident of India and as far i know there is no local broker.

plz answer
thanks in advance

I think there are separate regulations for countries like India you gonna have to find it out but I am pretty sure you dont need to pay the U.S. tax