You can be “served “by anyone really. Atleast here in Cali. He can have one of his friends do it if he wanted too lol
It depends on the state. Sometimes the police will serve you sometimes I can be through the mail.
Not sure how the states work, but in Ontario Canada, you have to have proof of you getting served or have the papers handed to you in person. Usually the lawyer asks for a signature upon receiving the papers.
You will get served by the police