how do I request a copy of my employment file from employer, what is my employer required to give me

Additional information
Let me explain further.

I resigned last year as a city employee and am looking into federal goverment jobs for the beginning of next year and ongoing. For some reason I would like to know what's in my record. I have been getting the interviews but no offer, now either I am a bad interviewer [I have made that the first reason] or its my references. So here I am looking into what I need to do prepare for these government jobs or other employer.

I look up under the Public Right to Know act in Maryland and call the previous employers to find out the fees. It's stated that some businesses will require a fee. I needed to know this so I can include it in my letter to them. I am told that I can only get it with a supoena or court order and would not state why.Is this true?

what can I do get a copy of my personnel records.