Re: People pay your Taxes

How do we pay taxes on BTC and how do we show it in our accounts?

You should pay taxes in INR, the same way you will pay taxes normally.
Depending on how you earned/made profits on bitcoin, you should classify it accordingly (other income/ capital gains)

What if someone is 18> years and making 500k+ inr every year then is it necessary for him to pay taxes ?

Yes. Age really doesn't matter in this case.
Even in the case of minors, income is clubbed with that of the guardian and income tax has to be paid.