Binance has been the most popular CEX since I entered the crypto world, it's exchange app quite easy to comprehend and it's always placed no.1 according to CMC ranking based on 24hrs Volume.
Other exchanges like Upbit, Coinbase, OKX, Bybit, Kucoin, Bitget, Gate.io etc are also known and popular CEXs which are also very easy to use and offer users reliability and easy accessibility.
For time now, I make use of Gate.io for my crypto trading.