Is trading on the stock exchange of a non-Islamic country in shares of companies whose products are permissible (halal), while avoiding companies involved in prohibited activities, permissible, or does it fall under the category of gambling? And what is the ruling on trading in futures contracts?

It is not enough to ensure that the company's activity is permissible; it must also not borrow or lend with interest (riba). Therefore, it is not permissible to buy shares in a company that deals with riba, even if its primary activity is permissible. This is what the Fiqh Academy has decided. However, if the company is pure, its activity is permissible, and it does not deal with riba, then it is permissible to buy and sell its shares.