Zero Crossing
A zero crossing is a point where the waveform crosses the zero level axis. To perform editing operations such as cutting, pasting, or dragging, we recommend inserting the audio material at a zero crossing.
If you do not perform these operations at zero crossings, this can result in discontinuities in the wave, which are perceived as clicks or pops in the sound.
Activate Zero-Crossing on the Edit tab of the Audio Editor to ensure that any selections you make start and end at the nearest zero crossing.