Are you looking for your RETS password to use in MLS Connect via zipForm? A RETS password is not your Flexmls password, it is a different password. You must set your RETS password in Flexmls after you have logged-in to Flexmls.
Setting / Changing Your RETS Password
Under Preferences go to My Profile. In your profile, click on RETS Settings.
Here in your RETS Settings you can set / update your password. Just enter a new password. Unlike most passwords, your RETS password will never expire or require changing.