Watch the C Major 7 Chord Inversions online guitar lesson by Frank Vignola from Inversion Excursion

Now that you have a good grasp on the triads let's move on to adding extensions. We start with adding the major 7th to the triad to make a C major 7th chord. Remember: a triad is a three note chord consisting of the 1st, 3rd and 5th step of the applicable scale. In this case C, E and G spell the C major triad. Adding an extension to the triad creates a 4 note chord. In this case we are adding the 7th step of the scale to the C major triad. The 7th step of the C scale is B or the major 7th. So the spelling of a C major 7th chord is: C-E-G-B or 1-3-5-7. Let's start inverting. In this case, when playing the B in the bass this is considered the 3rd inversion. Root position has root in the bass, 1st inversion has the 3rd in the bass, 2nd inversion has the 5th in the bass and the 3rd inversion has the extension or in this case the 7th in the bass. For each inversion, look at the chord and pick out each of the chord tones naming the notes.
PLEASE NOTE- The 1st inversion of these inversions involves a bit of a stretch. Visualize the chord before playing it and it will make it easier to stretch your fingers into place.