Im a girl 20 years old , is it possible to increase your height to 5 inches or more ?

Not easy: It is possible but very difficult to increase your height after you have stopped growing. The growth plates on your long bones closed up years ago, and the only way to increase your height is a lengthy and painful surgical procedure to break your long bones (your femur and or your tibia) and use fixators to hold the bones in place while they heal. Takes many months or years; its not for most.

High heals: The potential additional length anyone can expect depends on areas in the long bones (arms, legs, fingers)called growth plates.This is where growth occurs and an active open growth plate means more growth is possible. An xray of the hand/wrist can be evaluated for bone maturity.If your bone maturity is >18yo you are done growing taller.