Magento Community Edition, 1.9.x
Your store can be configured to require that customers open an account before making a purchase, or to allow unregistered guests to go through the checkout process.
To allow guest checkout:
|1.||On the Admin menu, select System > Configuration.|
|2.||In the panel on the left under Sales, select Checkout.|
|3.||Click to expand the Checkout Options section.|
|4.||Set Allow Guest Checkout to “Yes.”|
|5.||Click the Save Config button.|