A guest account is created when you choose to make a payment without creating an account, the payment is made as a guest and only an e-mail address needs to be entered.
If you want to find your documents later, you can simply log in with your e-mail address and click on “Forgot your password”. Then create a password for your guest account and make it a “normal account”. This way you can find all your documents that you have purchased on the guest account.
Are you not able to log in? Click here for more information.