If you want to change or have lost your password, you can reset your password using the following link: https://www.bitfinex.com/password_resets/new
Alternatively, you can find the "Forgot your password?" link on the login page as displayed here:
Note: if you have 2FA (SMS, Google Authenticator or U2F) enabled on your account, in order to reset your password you will need to have access to your 2FA token or key.
If you have lost both your password and your 2FA code, please get in touch with our support team via https://cs.bitfinex.com and select "Account Access" as first option.