You can choose which type of icon appears in the macOS Dock when your virtual machine is open or running.
Note: This feature is not supported in the App Store edition of Parallels Desktop. For more information on the differences between the Standard and App Store editions, follow this link.
Do one of the following:
Click the Parallels Desktop icon in the menu bar and choose Preferences. Then click General.
Right-click the Parallels Desktop icon in the Dock and choose Preferences. Then click General.
From the Virtual Machine Dock Icons menu, choose one of the following:
OS Icon: The Dock icon shows the icon of the operating system installed in the virtual machine.
Live Screenshot: The Dock icon shows a miniature image of what you see in the virtual machine.
None: Virtual machines don't have separate icons in the Dock.