You and your spouse will need to obtain your marriage license from the Clerk of the Court in the county or city where one of you resides, or anywhere in Virginia.
The courts accept cash or check only; usually no debit or credit cards.
Once you have received your license, there is no waiting period, and no witnesses are required to be present; however, there is a 60 day window between obtaining the license and the date of the ceremony.

If it's a quick and very private ceremony you want, NO PROBLEM! No one else needs to be present.