Your Wordpress user and password are something that are specifically defined when installing Wordpress for the first time. If you are unsure of your password, you may reset it using the following instructions:
There is an easier way. I have updated the article on recovering your Wordpress admin password to also include the option of click on the "Forgot Password?" button that is located below the login form. As long as your email address on the user matches an email account that you have access to, you will be able to recover your password that way as well.