In the Player controls:
iOS, Android: tap on the Mixer button (second one from the right at the bottom of the screen) to change the Count-in settings. (In case you can't see the count-in when you open the mixer, scroll down to reveal it.)
Mac: the Player controls is the right panel. (View menu>Maximise/Minimise Player controls).
 
Select zero for No count-in and set the volume of the count in with the slider.
You can also change the click sounds.
The Auto setting will automatically play one or two measures - depending on the tempo allowing more time for faster tempos before it starts playing.
 
 
 

Keynote

New in v2025.2

Select "Keynote" in Click 1 to sound the root of the key of the song for the count in (useful for singers to pitch from.)

For example, a song in the key of D, the note D will be heard instead of clicks.