What move works on Shedinja?

Answer 1

If by "best" you mean most damaging:

Shadow Ball does the most special damage and

Shadow Claw does the most physical damage (physical damage is Shedinja highest stat)

(both get a bonus for being ghost type moves)

But you may find that Shedinja is better suited to being an 'annoyer' so moves like Confuse Ray (confuses the enemy) and Mud Slap (damages the enemy and puts down their accuracy) are better.

Actually(i didnt write the above)

i disagree

i would choose Shadow Ball and Shadow Claw, but I'd also include Fury Cutter and Mind REader.

KEEP mind reader because at a high lvl shedinja learns a 1 hit ko megahorn and you need mind reader to make it hit

Answer 2

The moves that Shedina can learn through level up are Harden and Scratch as start moves and it can also learn Leech Life at Level 5, Sand Attack at Level 9, Fury Swipes at Level 14, Mind Reader at Level 19, Spite at Level 25, Confuse Ray at Level 31, Shadow Sneak at Level 38, Grudge at Level 43, Phantom Force at Level 47, Heal Block at Level 50 and Shadow Ball at Level 59.

Answer 3

any super effective move will do fine such as fire, flying, etc.