No special requirements needed for virtual subcontractor. All submission you give the government will be at your own discretion.

Hello,
Well it depends on your country of residence and the country of residence of your subcontractor.

However, what do you mean by "virtual"? They will work for you remotly but not virtual, right?

When hiring an overseas subcontractor, you should be mindful of both U.S. law and the laws of the local jurisdiction where your contractor lives or operates. When you hire a subcontractor in the U.S., you generally collect a signed Form W-9 from the contractor, which lists the contractor's name, address, taxpayer type and U.S. tax identification number (either the taxpayer's social security number or employer identification number). You may also be required to file a Form 1099 at year end to report the amount of gross payments made to the subcontractor. When hiring a non-U.S. contractor, you must still collect an IRS withholding certificate in order to verify the individual or company is not a U.S. tax resident. Individuals sign a Form W-8BEN, a corporation would complete W-8BEN-E, while a foreign partnership would complete a Form W-8IMY. It's also best to have a written and signed contractor agreement in place. You want to ensure that the relationship between you and the contractor is truly a subcontract relationship, and you do not create an employer-employee relationship.