The E chord (major): notes E G# B, degrees 1 – 3 – 5. Guitar shapes: 022100, xx2454, x76454, x79997.
A chord is the root plus degrees above it, most often stacked in thirds. Major and minor differ only in the lower third: a major third (M3) sounds bright, a minor third (m3) sounds sad. Pick a chord and a root to see its degrees and intervals, and its shapes.
m — minor, M — major, P — perfect, A — augmented interval; the number is the degree count. m3 is 3 semitones, M3 is 4, P5 is 7
E Em E5 E7 Em7 Emaj7 Esus2 Esus4 Eadd9 E6 Em6 E9 Edim Edim7 Em7♭5 Eaug