OPS: OPS stands for “Other Personnel Services”. This is nothing but a fancy name for Student Employment. There are some restrictions to be eligible for OPS however. You must be enrolled as a full-time student, must not be a Graduate Assistant, or resident. Also, your employment must not interfere with your study, and you are not allowed to bunk class and go to work. You can find more information here.
FWS: FWS stands for Federal Work Study. FWS applies mostly to US citizens, nationals or permanent residents. Feel free to ignore FWS jobs if you are an international student. According to UF’s website: “The purpose of Federal Work-Study (FWS) is to provide students with part-time employment to help meet college costs and, if possible, provide work experience in a related field. FWS is federally funded and need-based. Your eligibility is determined from information you provide on the Free Application for Federal Student Aid (FAFSA). To be eligible, you must show need on your federal need analysis report.”
Bottom Line: As an international student, you are eligible for OPS jobs. Otherwise, you are eligible for both.