iam sorry that didtn make sense but i wanted to know how people sing to songs but the song is playing but the person only moves their lips to the words so it looks like their singing but they are not how do they do that
something like this might help:
how does he do that without talking it hes just moving his lips to the song.
In addition to what the others said, here is how it works in a little more detail:
When you speak, sing, you are using air to travel through your vocal chords, which vibrates the chords so that sound comes out. When you whisper, you are using that same air, but shut off the vocal chords. In order to lip sync, you must shut off the air flow through your larynx completely, thus only moving your lips.