It means that you do not just log in with your e-mail address and your password but that there is a second factor on top of that. This may be a code which is generated, for example, via smartphone or is sent out by e-mail. So, even if someone does know your password, he or she cannot log in to your account. Two-factor authentication has been a standard for online banking for quite some time now.
Logging in with the two-factor authentication is optional for customers. You can set it up and deactivate it at any time. You can find the setting up options on the Online Portal under My details. We recommend that you use the two-factor authentication in any case in order to protect yourself from identity theft and a leakage of sensitive data. In addition, your customer account is then optimally secured.
Logging in should generally be as quick as before. Entering the second factors only takes a few moments.