How do bar chords work and how can I effectively play them on the guitar?

Bar chords are a type of guitar chord where the index finger acts as a movable capo, allowing you to play chords in different positions on the neck. To play them effectively, place your index finger across the fret you want to bar, then use your other fingers to form the rest of the chord shape. Practice applying even pressure with your index finger to ensure all the notes ring out clearly.