Certificate of Mailing (Form DC-413 (PDF) - Instructions (PDF)) can be filed in the Clerk’s Office to serve as substituted service, no less than 10 days before trial. This form certifies that you mailed notice along with the petitions/motions you filed with the court, via first class mail, to the opposing party.
Read Virginia law regarding service of process (Virginia Code § 8.01-296(2)(b)).