The best way to buy and sell cryptocurrency is to use a reliable online exchange such as Coinbase, Kraken, or Binance. These exchanges provide traders with a secure platform to buy and sell digital assets, while also offering features such as security protocols and customer service. Before making any trades, it is important to do research into the exchange and make sure it is trusted, reputable, and offers competitive fees. Additionally, you should consider using a wallet to store your digital assets for extra security.