Want to add something to users
As in Past we had seen One of the top bitcoin exchange had been crashed because of stolen BTC amount. and that amount of huge and many users did had lose their money.
Today, Although the exchanges have cold storage. but With that the high prices of BTC and other Cryptocurrencies does take higher risks of being stolen.
For that I would recommend is either ledgers or Other wallets they can be either desktop wallets or mobile wallets. which does provide you extra layer of security. You can keep your holding amount into these wallets (either hardware wallets like ledgers or Desktop or Mobile Wallets like exodus) to keep an extra layer of security and only trading amount to your exchange accounts.
RE: How to buy Bitcoin (or any CryptoCurrency)