If you are new to crypto trading, and looking for a platform to trade, here are some platforms I use.
Share with all of you

1.
Binance (Strongly recommended)
2.
Bitfinex (Stable, not many coins available)
3.
Bithumb (
ps:security issue happened, consider well)
4.
Upbit (Korea exchanges)
Welcome to other suggestion

*******Additional information************
Recommended by FlamingFingers :
Bittrex - 2 years exp. and No issue ever
Binance is the most trusted and popular excahnge at this time number one people choice because they gives better services. I also recommend the newly and realable platform exchange with full security feature nexybit trading platform.