The short answer
In Florida, certified process server usually refers to a person who has been approved through a court or circuit program to serve process where that program applies. Service of process means formal delivery of legal papers with proof. Certification is not the same thing as being a lawyer, and it does not let a server give legal advice.
Florida Statutes section 48.021 addresses who may serve process. It recognizes sheriffs, special process servers appointed by the sheriff, certified process servers in counties with certified-process-server programs, and people authorized by the civil rules for civil witness subpoenas. The exact authority depends on the document, county, and program.
Practical note: Certification is about service authority and local court administration. It is not a promise that a particular serve is valid in every case.
How certification differs from licensing
A private investigator license is a business and investigative credential. Pro Legal Serve is a licensed Florida investigative agency, FL PI Agency License #A3300059. That credential supports lawful investigative work such as address verification and skip tracing, but it is different from court certification for process serving. In practice, clients should treat these as separate checks: who may serve this document, who is performing any investigative support, and what proof will be returned after the field work.
Professional associations are also different. NAPPS and FAPPS membership signals industry participation and standards, but association membership is not the same as court appointment or statutory authority to serve a particular document.