O.C.G.A. § 29-9-8 (2019)

(a) Service or notice may be waived or acknowledged before or after the filing of the petition. The waiver or acknowledgment of service shall be in writing, signed by the person to be served or some person competent to do so, shall be sworn before the court or a notary public, and shall be filed with the court.

(b) The written consent of a party to the granting of any relief or the entry of any order sought in a proceeding, whether executed before or after the filing of the petition, shall constitute a waiver and acknowledgment of notice and service of the proceedings, waiver of citation, entry of appearance, answer admitting all allegations of facts set forth in the petition as true and correct, and consent to the granting of the relief or the order sought.

(c) A person in military service, regardless of age, shall be permitted to make any waiver, acknowledgment, or consent described in this Code section.