Yahoo! allows you to access several services by using a Facebook or Google ID in association with OpenID. If you are accessing Yahoo! using one of these services, you need to log in to Yahoo! using the username and password provided by the service that you signed up with. If you are unable to sign in to Google, Facebook, or the Open ID service that you chose, you will need to contact those companies directly for password assistance.

To change your password, you need to be logged in.

1. From any Yahoo! site, select your username in the upper-right (or upper-left) corner. 
2. From the pull-down menu select Account Info. (You will be asked to sign in again before you can access your "Account Info" page.)
3. Select Change your password. You will be automatically directed to the password configuration page for the service that you signed up with.
4. Follow the instructions to enter your current and new password.