If you're just looking to buy bitcoin with fiat, Coinbase would probably be a good option if they're available in your country. I'd advise staying away from the lesser-known exchanges altogether and sticking to the bigger, more well-known ones. There have been so many scam exchanges, hacks, and everything else that you have to be really careful.
Coinbase isn't available in too many countries so people from developing countries might have hard time while converting their fiat into cryptos for the first time.
Bisq can be an option for someone who is looking for a decentralized p2p trading method so they can do trades even if their countries have banking restrictions.But I always suggest LBC for someone who is really new to buying cryptos where chances of losing money are less but stay away from hacked accounts is the real task for anyone.