The core of the auto-tune process lies in the interface. If using the GSnap plugin, the user navigates to the "Effect" menu and selects the tool. This opens a visual representation of the piano keyboard and a display showing the waveform of the vocal. The most critical setting here is the "Key" and "Scale." If a song is in C Major, the user must tell the software to only allow pitches that exist in C Major. If the wrong key is selected, the software will attempt to correct the vocals to notes that clash with the music, resulting in a dissonant, chaotic mess.
In the Audacity waveform, select the vocal track you want to autotune. You can do this by clicking and dragging your mouse over the section of the waveform that contains the vocals. how to autotune in audacity