Next to the "Log in" button under the enter login andpassword, usually there is a button "forgot?" or "forgot password?".The most common scenario after you click this button to restore the password to the e-mail address provided during registration. You will be prompted to enter the e-mail to which you registered your account on this website and then confirm your password reset click "OK" or "Restore". After that e-mail will receive an email with a link, clicking on which, you will be prompted to enter a new password, usually twice to confirm the correct input.
Some resources propose to correctly answer a security question that you choose yourself from the available list of questions at check-in. Usually these are questions like "mother's Maiden name", "passport Number", "Last 6 digits of INN, "a Nickname first pet".
Another option for password recovery, which is increasingly rare – it is a requirement of the site to specify additional e-mail address that was entered when creating your account. This e-mail will receive your pair of login andpassword, with the password usually remains the old, and to change it you can in the account settings after logging in.