As you learned in our "Facebook Login and Sign in settings" tutorial, the Facebook sign in page (screen) is the first line of defense that protects access to your account through the Facebook login process. As you'll see in this tutorial, there are several versions and variations on the sign in screen, but all achieve the same result, and work in exactly the same way: the sign in form will collect your user name (email address) and password, and the login settings you choose with the "Keep me logged in" checkbox (if you want to automatically login to your Facebook account), and send all this information (your "credentials") to their servers for authentication. What happens next depends on whether you supplied the correct information, or if your email address or password contained a typo.
When you type "www.facebook.com" inside your web browser's address bar and hit Enter, you will either be automatically signed in to your account, or you will see the Facebook sign in form in the top right corner of the screen (as shown on the screenshot further down), or in the middle of the page.
If you are logged in to your Facebook account, this is the end of it: you will periodically see the sign in form whenever Facebook automatically logs you out (for security reasons), and you will see what we describe next (except for third-party plugin or web browser settings, which can affect the behavior of all login form you have encountered in the past). Here is a screenshot of the default Facebook sign in page (the screen displays a form in the top right corner of the homepage).
The two mandatory fields are "Email" and "Password": you need to enter the email address you used when you first signed up to create your Facebook account. Note that your email address is case-insensitive, which means that Facebook will not care about uppercase or lowercase letters for the email text field of the sign in form; the password field, however, is case-sensitive: you need to enter your password exactly as you chose it the first time you signed up for Facebook (or the last time you manually changed your password). Once these fields have been filled out, you can hit the Enter key (Windows or Linux) or the Return key on Mac OS X. This is the sign in form in its most basic functionality.
In much the same way as Hotmail Sign in, the Facebook sign in screen includes a checkbox for convenient login sessions in the future: the "Keep me logged in" checkbox is described in more details in our Facebook login tutorial. (In a few words, it tells Facebook that you want to automatically sign in to your account in the future - the assumption being that you are checking your profile from a safe computer.)
If, before you click on the "Login" button or hit Enter / Return, you check that checkbox, Facebook will notice it during the sign in process, and if the user name and password you entered were correct, a "cookie", or small text file, will be created on your computer, for this particular browser, and instruct Facebook to automatically login to your account next time you access it.
For all Facebook users' security, no-one can login to Facebook without a password - so, what happens if you forgot your password? Notice that the sign in form includes, below the password field, a link that reads "Forgot your password?" Clicking on this link will guide you through the password reset and recovery process, which allows you, in most cases, to regain access to your profile and account.
For more generic information, you can check out our Facebook tutorial.