When you connect to a device using RealVNC Connect you see the entire desktop of the remote device, regardless of how many monitors it spans. You can cycle through or select a particular remote monitor to view or you can use the parameter system to restrict RealVNC Server to only remote a particular monitor if you wish.
The resolution of the remote access session is controlled by the remote device you are connected to, for example connecting to a device running RealVNC Server with a 4K monitor attached to it means that the remote desktop will be remoted at 4K.
Connecting to a headless device running Windows?
You may find that your remote access session is limited to a small resolution. Click here to find out more.
By default, the remote desktop is automatically scaled to fit by RealVNC Viewer. You can display the remote desktop at its actual size using the Scale to 100% button on the RealVNC Viewer toolbar which is available at the top of the session window while connected to a remote device.
For more control, you can use the Properties dialog: