VMware Workstation is a hypervisor or a virtualization software which allows to install multiple operating systems on the same computer. These virtual installations (operating systems inside another operating system) will reduce hardware costs and can be used to test applications in different environments.
It allows to install all versions of Windows and different versions of Linux. You cannot install Mac OS.
You can customize each guest machine (CPU, RAM, HDD), share folders, copy files using the Copy function of your mouse or drag&drop. You will be able to use the USB, printer, DVD/CD-ROM, video and sound cards from host on guest machines.
You can take snapshots (backups) for each guest machine and revert the status of guest with a single click.
You have access to BIOS for each virtual machine.
It provides detailed documentation, there is a forum where you can read tutorials, ask questions and read tips for improving the performance of virtual machines.
This program offers many advanced features to customize and to work with virtual machines using a professional interface.