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

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