business of financial markets

Salam!
My question is that what if anyone from Pakistan is in the business of financial markets as an individual and does trading in the financial markets with his knowledge. Is his earning legal or not? Is he be able to pay tax or not? If he is doing legal work and tax is payable by him then how can he show his earnings and become a tax payer? As far as i know, currently Pakistan government has declared that freelancers are free from paying tax so trading in financial matkrts is also kind of a freelancing. Please clear all my thoughts and explain to me in simple words. Jazak Allah!