Hi and welcome.
You will need to reset your password ***** using the Forgot your password link found on Yahoo Mail's website.
There are three options to recover your password, please proceed to the following link and reset your password ***** the best method for you:
Once you have your new password, you will be able to log into your account.
If you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.