Here is how to use the autotune in adobe audition.
1. Select the vocal take you'd like to apply auto-tune to in the Multitrack Editor. Right clicking on the file brings up a few options, find "Edit Audio File." Click it to open Audition's single-track view.
2. Scroll through the "Effects" options menu. Select the "" menu, followed by the Pitch Correction (Process) effect to open up the main auto-tune dialog screen. here you can adjust the parameters of the auto tune before applying it.
3. Use the appropriate level of autotune. The dialog lets you choose the amount to apply, the scale to use (hit "chromatic" and crank up the level if you want the autotune effect that rappers use these days) and if necessary it gives you a manual autotune that can be more accurate, depending on your goal. Use a very subtle amount of Audition's autotune effect if you don't want it to be noticeable. Applying the subtle autotune effect a few times is enough to clear up most shaky vocal takes.
4. Hit apply. It'll take some time for the auto-tune to be applied.Done.