To purchase cryptocurrency, you can use an online exchange or an over-the-counter (OTC) broker. Using an exchange is the easier option, where you can sign up for an account and purchase various cryptocurrencies using a bank transfer or debit/credit card. Some exchanges also allow you to purchase cryptocurrency with other digital assets, such as Bitcoin. Additionally, OTC brokers act as a middleman and facilitate transactions between buyers and sellers of cryptocurrencies through escrow services.