NY CPLR § 308 (2021)
2021 New York Laws CVP - Civil Practice Law and Rules Article 3 - Jurisdiction and Service, Appearance and Choice of Court 308 - Personal Service Upon a Natural Person.

§  308. Personal service upon a natural person.  Personal service upon   a natural person shall be made by any of the following methods:1. by delivering the summons within the state  to  the  person  to  be   served; or2.  by delivering the summons within the state to a person of suitable   age and discretion at the actual place of business,  dwelling  place  or   usual  place  of  abode of the person to be served and by either mailing   the summons to the person  to  be  served  at  his  or  her  last  known   residence or by mailing the summons by first class mail to the person to   be  served at his or her actual place of business in an envelope bearing   the legend "personal and confidential" and not indicating on the outside   thereof, by return address or otherwise, that the communication is  from   an  attorney or concerns an action against the person to be served, such   delivery and mailing to be effected within twenty days  of  each  other;   proof  of  such  service  shall  be  filed  with  the clerk of the court   designated in the summons within twenty days of either such delivery  or   mailing, whichever is effected later; service shall be complete ten days   after  such  filing;  proof  of  service  shall  identify such person of   suitable age and discretion and  state  the  date,  time  and  place  of   service,  except  in  matrimonial actions where service hereunder may be   made pursuant to an order made in  accordance  with  the  provisions  of   subdivision  a  of  section  two  hundred  thirty-two  of  the  domestic   relations law; or3. by delivering the summons within the state to the agent for service   of the person to be served as  designated  under  rule  318,  except  in   matrimonial  actions  where service hereunder may be made pursuant to an   order made in accordance with the provisions of subdivision a of section   two hundred thirty-two of the domestic relations law;4. where service under paragraphs one and two cannot be made with  due   diligence,  by  affixing  the  summons  to the door of either the actual   place of business, dwelling place or usual place  of  abode  within  the   state  of  the  person to be served and by either mailing the summons to   such person at his or her last known residence or by mailing the summons   by first class mail to the person to be served  at  his  or  her  actual   place  of  business  in  an  envelope  bearing  the legend "personal and   confidential" and not indicating  on  the  outside  thereof,  by  return   address  or  otherwise,  that  the  communication is from an attorney or   concerns an action against the person to be served,  such  affixing  and   mailing  to  be effected within twenty days of each other; proof of such   service shall be filed with the clerk of the  court  designated  in  the   summons within twenty days of either such affixing or mailing, whichever   is effected later; service shall be complete ten days after such filing,   except  in  matrimonial  actions  where  service  hereunder  may be made   pursuant  to  an  order  made  in  accordance  with  the  provisions  of   subdivision  a  of  section  two  hundred  thirty-two  of  the  domestic   relations law;5. in such manner as the court, upon motion without  notice,  directs,   if  service  is impracticable under paragraphs one, two and four of this   section.6. For purposes of this section,  "actual  place  of  business"  shall   include any location that the defendant, through regular solicitation or   advertisement, has held out as its place of business.