18 by One Direction is in A at 124 beats per minute and runs 3:23 across 82 bars. It uses 7 chords — A, F#m, Dmaj7, D, E, N.C., F#m7. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? 18 guitar melody tab.