The easiest way for US customers to buy Bitcoin is using the "Buy Instantly" button (AKA smash buys). By clicking that button you purchase Bitcoin immediately at the current market price and then are billed for it afterward from the current bank account you have on file.
If you need help with connecting your bank account, please read this article.
To make these instant purchases, first, scroll down to the middle of your dashboard and click on the "Buy Instantly" button. Then a popup window will allow you to select how much you wish to purchase. Note that we have a $100 minimum. After you click "Next", you will see a confirmation screen with the current price, fees, and the bank account that will be charged for that purchase. After clicking "Buy Now" you will receive a congratulatory screen.
The entire process can be seen below:
If you are an international customer or looking to purchase more than your current limits, then you should wire funds into your account.