VNC Connect does support multi-factor authentication, to protect your account, your computers and your data wherever you are.
Note that VNC Connect has two separate password systems, so no one credential controls remote access to your computers. You can protect both systems with two or more factors.
RealVNC account password
We strongly recommend you set up 2-step verification for your RealVNC account. To do this, sign in online and follow the instructions on the Security page.
Any applications that generate 6 digit time-based one-time passwords (including Google Authenticator, Authy) are supported. SMS is not currently supported.
Note that if you have an Enterprise subscription, you can mandate that all the people you've invited into your team to share remote access must enable 2-step verification on their own accounts. Failure to comply prevents remote access. More information.
VNC Server password
You can set up multiple authentication schemes for the computers you want to control, for example using single sign-on (SSO) or X.509 certificate authentication. For more information, start with this article.