It's a 6-digit code (sometimes called an OTP, or one-time password) that only works once and expires in about 30 seconds. Even if someone somehow got your password, they'd still need this code to get in. It's your account's bodyguard to double-check it’s really you.
Think of it like a single-use key. Once you use it, it’s gone.
Why do we use it?
Your super is your money for the future and protecting it is serious business. Your one-time code helps keep your account safe as it's an extra layer of protection on top of your password.