Why can't you get them yourself off of the company's web site? Many cell phone companies have this. Do you have a lawyer working on your case? If YES, the lawyer should do this. If NO, go see the pro se Clerk at the court for guidance. You don't say what kind of case you have, but its a mistake for a non-lawyer to try and represent themselves.
Generally speaking subpoenas are issued by the Court. While you can go to the Court Clerks office and obtain the forms and some instruction, an attorney would be more familiar with the pricedural ins and outs.