O.C.G.A. § 22-2-133: Service of process generally.

All persons entitled to notice under the facts stated in the petition who are sui juris and within this state and whose residence is known shall be served by the sheriff with a copy of the petition and order as in other causes at law, unless such service is waived in writing. All other service shall be made in the method pointed out by Part 2 of Article 1 of Chapter 2 of this title, and all persons so served shall be deemed parties to the cause.