i am trying to ask the jail for names that my fiancee is writing or visiting
Civil Rights Attorney
The federal Freedom of Information Act (FOIA) applies to "public records" maintained by the federal government in the context of governmente business. If the records you seek are not federal public records, then the FOIA does not apply. The next question is whether the names of a jail inmate's personal correspondents are public records. Because such records (if they exist) are not records kept for the purpose of government business, it's unlikely they are subject to the FOIA, and in any event are private information not subject to disclosure.