Bitcoin can be bought through a number of online digital currency websites, including brokers like Coinbase and exchanges like Binance. Some of these brokers and exchanges will allow you to connect a US bank account or credit card to your account and purchase certain coins after a strict verification process. Others require you to obtain digital currency on a different exchange or brokerage and use those currencies to transact and trade on their exchange.
If you want to create a Coinbase account (and/or use the digital currency you buy to fund an exchange), you can learn how to do so in our tutorial: How Do I Buy Bitcoin (BTC) on Coinbase and Send It to an Exchange?
There are also options for investors holding money in retirement accounts (401K, Roth or Traditional IRA) to roll over their holdings into a Bitcoin IRA. Blockchain Beach wrote an investigatory piece on this that can be read here: Putting (Some of) Your Retirement into Digital Currency.
