How long does it take to play the chords in the electronic piano score?

The chords in the electronic organ can be improved by holding them down with the left hand while playing, instead of holding them down all the time. Chords are usually written on the first note of each bar in the score, which is also the first beat of this bar. So you can press the score and chord at the same time when playing. Every song is played like this. I feel that you can play and know something, and you will certainly understand what I say.