What would a law firm want in an intern who is trying to create an internship?

I am attempting to secure an internship prior to law school. I have no issues with simply getting coffee, answering phones, or any type of free labor. A lawyer told me to write a question in legal memorandum format and ask a question when hiring an intern that they would have to say yes to. Any info on what a law firm might be looking for would be very valuable!