C maj7
The C maj7 chord consists of the C (Perfect unison), E (Major third), G (Perfect fifth) and B (Major seventh) notes.

How to play the C maj7 chord
- Find C (Root) on the piano keyboard
- Add E (Major third) — 4 semitones above C
- Add G (Perfect fifth) — 7 semitones above C
- Add B (Major seventh) — 11 semitones above C
- Press all 4 notes simultaneously to sound the C maj7 chord