New York Laws
Article 8-A - Process Servers and Process Serving Agencies in Cities Having a Population of One Million or More
89-FF - Affidavits of Service.

ยง 89-ff. Affidavits of service. It shall be unlawful for a process
server to fail to set forth on any affidavit of service or process
signed by him his license or registration number if such process server
is required to be licensed or registered pursuant to any state or local
law and the name and address of any process serving agency from whom he
obtained the process for service if any.