First, you must be a US citizen. Then, you must apply to the academy (which includes academics, leadership, sports, medical, and extra-curricular aspects).
I have to ask, why the US Air Force Academy? There are fighter pilots in the French Air Force. The Mirage is a good aircraft, and the Rafale is excellent. What would make you want to be a US citizen and USAF fighter pilot? That is a question you must answer for yourself, before it is asked by others.