The arms are very easy to exercise, but it will take time to see results. Swimming, pilates, yoga, weight lifting, elliptical machines, baseball, tennis, basketball are just some examples of activities that work the arms hard. Do it enough and you'll get toned, assuming you eat a diet that doesn't metabolize quickly into fat and just makes the problem continue.
No best exercise for toning the upper arms; It's a combination of strength training to build your muscles, and decreasing body fat through calories. The best upper-body exercise that uses most of the muscles in your entire arm is the overhead shoulder press, Called the Arnold press. Do the Arnold presses twice a week as part of your upper-body routine to strengthen and tone your arms.
Exercise all three areas of your shoulders to build the right size and shape. Those areas are the frontal deltoid, medial deltoid and rear deltoid, and your biceps and triceps.
All three muscle groups are active doing the Arnold press.
The following link will show you how to do it.
https://www.youtube.com/watch?v=BWoN4Og7BEA