Having fat on your arms makes it look ugly and saggy on your hand. To reduce the amount of fat in your arms you need to diet first and this is for people who are over weight, you need to exercise which include weight training to burn off the fat, you can also have cosmetic surgery if you can afford.
Lift weights. If you do alot of arms exercises daily, it should be gone pretty fast, since fat turns to muscle semi easily. Try to focus on biceps triceps and forearms and go to your local gym so they can help you with some exercises.