For physical fitness certificate, you need to visit any government recognized physician or medical practitioner and then get a signed paper from him/her. The paper/ certificate should clearly state your name, father name, domicile, cnic. The certificate must state your measured weight and your height. It must contain your chest measuremnt i.e normal as well as expanded. Finally signature and office seal of concerned physician must be affixed.
Then send it to FPSC by clearly mentioning the case number and name of post applied for.