Two-Factor Authentication is an extra layer of security on top of standard password access. This usually takes on the form of a code generated either by email, a supported mobile application, or SMS.
Two-Factor Authentication helps to protect your account from hacking. It is a lot safer than password only access and should be used to give you extra peace of mind that no one will be able to access your account. While Two-Factor Authentication is not going to give you 100% security, it is a lot more secure than password only access.