AnyViewer is a great solution to view a Windows computer that has multiple monitors. See the detailed guide on how to use it.

Step 1. Download, install and run AnyViewer on your devices.

Step 2. Create an AnyViewer account and sign into it on both devices.

Step 3. On your local device, go to Device and click the remote computer with multiple screens and choose One-cilck control. 

Step 4. Then, you can view multiple monitors on the remote computer in your local window. If you only want to see only screen, go to controller toolbar, click Screen and choose the screen that you want to list. 

And you can do what you want to do as if you were sitting in front of the remote computer.