If you have more than one monitor plugged into your computer, it is possible to use all those monitors when connection to a remote computer with the Remote Desktop Connection application in Windows. Ensure that the remote computer also supports multiple monitors.
Follow the steps below to activate the option:
Step 1: Select "Show Options"

Step 2: Select the "Display" tab.

Step 3: Place a checkmark next to "Use all my monitors for the remote session"

Now all your monitors will be used when connecting to a remote desktop.