Hyper-V Virtual Machine Import Types
Register the virtual machine in-place (use the existing unique ID): This registers the VM to Hyper-V in place without changing anything (location/ID etc)
Restore the virtual machine (use the existing unique ID): This option is used when the VM files need to be moved to another location from the original location (for example, the VM might be on remote share, usb harddisk etc)
Copy the virtual machine (create a new unique ID): This copies the VM, for example, you might have template and want to just create a new VM from this template. this will create a unique ID each time, and register the VM in Hyper-V.
When the 2nd or 3rd option is selected you will be presented with more choices