my game when built on ios is not smooth.

Hi, please provide more context. Any relevant code snippets so we can understand how you are thinking, and what methods you've tried already.

Try performing those movements in Update using Time.deltaTime.

Why are you using FixedUpdate? Try transform.Translate with Time.delta time in Update(). Also, what does "not smooth" mean? Your object should not have a variable speed, but it may well be stuttery because iPads are clearly less powerful than PCs.

iPads are clearly less powerful than PCs.

It surprises me that they function at all :P

i tried Update() and Time.deltaTime and nothing changed.

by "Not Smooth" i mean you can see the circle like it moves from position 1 to position 2 then stops for 0.01 second then moves to pos 3 and stops for 0.01 second ......

edit#1:

i tried 2x AA and the circle movement was a little bit smoother but the game was soooo laggy