The best place place to buy or trade cryptocurrency is as follows:
This is my top five, It is important to note all these exchanges come with different fee structures and registration processes. Each one of them will bring you through a KYC process, this is required to purchase any cryptocurrency including bitcoin.
Coinbase insures their own platform against theft and hacking so that is why we choose them number one.
They all offer many cryptocurrencies and the ability to purchase in fiat currencies, except eToro, the fiat currency they exclusively deal in USD. If you want to purchase in a different currency I suggest you avoid them.
Coinbase is designed to make buying crypto as easy as possible
Coinmama makes it possible to buy bitcoin as fast as possible
Kraken has the lowest fees
KuCoin has the widest range of Altcoins available.
eToro allows you access to their API.
Payment methods is another important consideration, almost all the above accept bank transfer and credit card deposits but if you want PayPal deposit that might be difficult.
Customer service on all the above is exceptional.