Here's how to play a C major chord with an added 9th note - the Cadd9 chord. This is a chord with four fretted notes where as the regular C major has 3 fretted notes and these main notes are the C, E, G and then D note (the 9th). It's still a major chord just with an added major 9th, which gives the chord a distinct sound and shape, very close to the Big G shape.
Cadd9 & G chord
Why use the Cadd9 over the regular C we just learnt?
The Cadd9 goes really well with the Big G chord, easy change with shared notes
The Cadd9 is used in many songs we'll learn, including the Jam Tracks, plus it goes well with the D major too
The C major is quite a stretch, therefore the Cadd9 can be quicker in some cases
Get the D, Cadd9 and G under your fingers and you can play many different songs right away! (Sweet Home Alabama, Sweet Child o' Mine)
Chord Changes for D, Cadd9 & G