When you eat more calories than you burn, your body stores the excess energy as fat for later use. To reverse this process, all you need to do is eat less than you burn.
Fat = Unhealthy
High body fat percentages are associated with heart disease, diabetes and obesity. Getting rid of excess fat will make you healthier and you'll look better.
Reducing body fat is the same as losing weight in general. When you eat more calories than you burn, your body fat stores will increase. If you do the opposite (burning more than you eat) your body fat will decrease. Figure out how many calories you burn per day using the calorie calculator.
Make sure you are eating less calories than you burn each day and soon enough you'll see your body fat percentage go down. Exercise also plays an important role in reducing body fat. By running, biking, swimming or participating in some high intensity activity, you'll burn calories and reduce body fat.
Since muscle mass burns more calories than fat mass, one of your long term priorities should be to build more muscle through a strength training routine that includes strength training.