Open shape
022000
Em is the E minor chord. Its notes are E, G and B. The lowered third gives this triad its darker color.
022000
x79987
Numbers show frets from the low E string to the high e string; x means don't play that string.
Em is the ii chord in D major, the iii chord in C major and the vi chord in G major. That makes it a natural fit in songs written in those keys.
Every E, G and B on the first 12 frets. The filled dots are the root, E. Build your own shape from any nearby group.
Other E chords
Other minor chords