How can my overweight friend lose weight?

MY FRIEND IS REALLY OVERWEIGHT AND SHE DOESNT KNOW what 2 DO what CAN SHE DO CAUSE SHES REALLY WORRIED ABOUT HER WEIGHT AND SHES LIKE 110 LBS AND 5"2 HOW CAN SHE LOSE WEIGHT SHE WANTS 2 B 100 LBS

That is actually about right for her, she is not overweight at all! Maybe she would just like to tone up or whatever, but 100lbs is considered underweight.

She is at 20.1 right now

Below 18.5 Underweight
18.5–24.9 Normal
25.0–29.9 Overweight
30.0 and Above Obese

If she were 100lbs, she would be at 18.3

Sounds like "Your Friend" is really you, heh.

110 pounds is a healthy weight.

110-115 is the normal weight class for someone who is 5'2. If your friend wants to be at 100 thats just really unhealthy first of all and she will look grossly skinny. Your friend is fine with the way she is and you should be encouraging her and telling her she is beautiful the way she is

Well,This is normal weight.Dont worry.She will just look fine,^^

If you're really talking about your friend and not you, first of all, you're a horrible friend if you're letting her believe that 110 pounds at 5'2" is "really overweight".
110 pounds for her height is the perfect weight.