Help Me Lose Weight

Actually, this is for my friend. She came to me for help and I said I would help. But I want it to be right so I came to this site for any postotive input.
My friend is a girl and she is 141 pounds and wants to get to 120 pounds by september 20th or close to it. she wants a flat stomach and to lose size around her legs, ass, and stomach. Please give me some suggestions on workout plans or something, please.

Does she work out now? What is she eating now? How tall? Does she realize that you don’t know too much? Cmon, details.