We do not require you to have or create an account. You can simply choose "checkout as a guest" at checkout.
However, we strongly encourage our customers to create and use an account. Having an account provides for a faster checkout and access to orders and items history (with easy re-ordering buttons).
You can create an account by either going
here and clicking "Create an account", or, when you checkout as a guest you'll have an option to create an account at the end of the checkout process.