VNC Connect (VNC Viewer and VNC Server v6.x)
Home and Professional subscriptions
There is no license key. Instead, you license VNC Server (running on each computer you want to control) by signing in to it using your RealVNC account credentials (email address and password).
You should have been prompted to do this when you installed VNC Server. If not, open the VNC Server menu from the taskbar and select Licensing:
Follow the instructions to Sign in to your RealVNC account.
You can license VNC Server in the same way as above, by signing in using your RealVNC account credentials on the remote computer you want to control.
VNC Server 5.x (legacy software)
A licence key for the legacy VNC Server 5.x software is available with an Enterprise subscription, so you can remotely access old platforms that are not supported by VNC Connect. This is available from the Deployment page of your RealVNC account.
VNC Viewer Plus
If you have purchased VNC Viewer Plus, your license key is available on the VNC VIEWER PLUS page of the VNC Connect portal.