The best and world's leading exchange for all nationalities including Pakistanis is Binance as far as trading, investing and staking is concerned. Security of funds is also guaranteed by some kind of insurnace coverage . The volumes are Huge so selling/buying orders are executed within seconds. It is better to complete KYC after opening your account so that deposit and withdrawals of funds won't be any issue.

https://www.binance.com/en