Where major and minor triads have 3 different notes, 7th chords have 4. The major seventh chord refers to where the “seventh” note is a major seventh above the root . This is also known as the major/major seventh chord, and it can be written as maj7, M7.
Major 7th chords are different than dominant 7th chords (whose 7th is flattened).
For example, let’s take a look at the C Major Scale:
Now let’s take the Root (1st step), 3rd step, and 5th step of the scale
(in parentheses below):
Therefore a Cmaj7 chord would have the notes C, E, G, B (the B being the extra note).
A Shape Major 7th Barred
(audio example is DM7 with it’s root note on the 5st fret)
E Major 7th
This chord is very easy to play. Just place your 1st finger across the 2nd frets of the G, B, and high E strings. To sound the chord just strum the D, G, B, and high E strings.
This shape is easy to barre: