N.Y. Comp. Codes R. & Regs. tit. 22, § 1963.1
3. Where, by court order, service of process is permitted by certified or registered mail it is not necessary to file a signed return receipt unless directed by the court. The affidavit of service, however, must include a statement that the mailing was not returned to the sender as undeliverable.
Pleadings and Papers Filed With Court
6. No party in interest in a proceeding can act as a notary public for any papers filed in the proceeding.
Status of the Parties; Proof of Kinship
Service of Process and Proof of Service