Open the Logic program, and then open the file that contains the vocals you want to autotune.
Click the desired audio track once to highlight it.
Click a blank slot under the "Inserts" menu located in the leftmost pane of the window. A menu should appear.
Select "Pitch," followed by "Pitch Correction," and then choose either "Stereo" or "Mono" (depending on what you're recording in). The pitch correction widget will appear on your screen. It looks like a small keyboard with several configurable options.
Click the box located below the word "Scale" to open a list of musical scale options. Select the scale that your song is in (for instance, major, harmonic minor, melodic minor).
Click the box below the word "Root" to open a list of options. Select the song that your key is in (for instance, A, Bb, C#).
Slide the "Response" slider all the way down. This will make the response time faster, which will give you the more computer-generated sound that has been popularized by many hip-hop/R&B artists.
Click the "X" button located in the upper left-hand corner of the pitch correction widget. Your vocals are now autotuned.