Sometime back we talked about Facebook planning to enable 2 step log-in authentication just like Gmail and other Google account services. The feature of 2 step Log-In Security is live now and majority of users can enable this security feature inside thier Facebook account security settings.

This security enhancement if enabled will help you secure your Facebook account by adding a additional layer of security. Apart from your password, you need to input a Code sent on your mobile phone from Facebook.

To enable Facebook 2 step log-in security (Called here as Login Approvals ), just Navigate to your Facebook Account >> Account settings >> Account Security. Just click on change and you will find a additional option of Login Approvals.

As per Facebook:

Login approvals is a security feature that requires you to enter a code that we text to your phone when you log in from an unrecognized computer. You can enable this feature in a few simple steps.
If you ever lose access to your phone, you can always return to a previously-recognized computer to regain access to your account.
Note: You’ll need to have a mobile phone with you to complete this process.

After you select the option of Login Approvals, you will be asked to add a mobile phone to your Facebook account  after it informs you what Login Approvals is.

After you add your mobile, a text message will be sent to your mobile to verify it. After you are done verifying it, the security code will be sent to your mobile which will be used for every Facebook login.

If your phone gets lost or stolen,then you can use a previously-recognized computer with facebook to regain access to your account.