From our last post on Building Piano Chords, you should be able to form root position chords in any key. Root position simply means that the chord is played with the root as the lowest note. (The root is the reference note for a chord: the tone the chord is built on and named after. The tonic is the reference note for a scale.)
For a C Major chord, the root position has C as the lowest (or bass) note. This is the normal form of a chord — for example, C, E. G.
When a note other than the root is in the lowest position, the chord is said to be inverted. The first inversion of a C chord has E as the bottom note, for example, E, G, C. The second inversion has G in the bass, e.g., G, C, E. These are labeled as examples because the notes above the bass note can be in any order, it is the lowest note that defines the chord form.
Mario Ajero does a nice job of showing inversions, and teaches you the intro to “Let It Be” along the way.