Real (or ordinary) parts should have a footprint associated with it, so you will be able to export your Multisim design file to Ultiboard for PCB layout.
Virtual components are only useful in Multisim, they are for simulation-only and don't have a footprint associated with it. Virtual components have a symbol and a model, but no footprint and hence are not “real” in the sense that they cannot be purchased or laid out in a PCB. They are included for simulation flexibility.
Regards,
Nestor
