A virtual manager is a tool or resource that allows for the management of more than one computer from a single workstation. This term may also refer to someone who is managing multiple computers remotely as a virtual manager, or may even be used to describe some kinds of specific software products and services.
Techopedia explains Virtual Manager
Virtual manager tools allow for a single work station monitor to display multiple desktops. This requires remote access and the security requirements attached to any given network. Many use the term keyboard, video, mouse (KVM) to refer to virtual manager setups, where the peripheral controls are used remotely to control an additional computer from a single location.
Virtual manager resources can help users to provide tutorials or training to other users. They can also enable remote fixes where a user may be having trouble with a given piece of software or an operating system. These tools broaden a user's capability to conduct more extensive work within a network or through a remote access protocol. Virtual management is also an important aspect of virtualization, where there’s a disconnect between a piece of software or an operating system and the hardware that is running it. Virtual manager tools can help accomplish this virtualization for the purposes of remote storage or any other reasons.