How is it that a song can use major chord on the supertonic degree so I have G F D and C chords in same song?

The use of a major chord on the supertonic degree (the second scale degree) in a song is not uncommon and can create interesting harmonic effects. In the case of a song using the chords G, F, D, and C, the progression involves a mix of major and minor chords, creating a sense of tension and release. Here's how this progression works:

1. G major chord: This chord establishes the tonal center of the song and serves as the "home base." It provides a sense of stability and resolution.

2. F major chord: The move from G to F introduces a major chord on the supertonic degree. This creates a bright and uplifting sound, adding a contrasting element to the progression.

3. D major chord: The progression continues to D major, which is the dominant chord in the key of G. The D major chord builds tension and creates a sense of anticipation, leading towards the resolution.

4. C major chord: Finally, the progression resolves to C major, which is the subdominant chord in the key of G. The C major chord provides a sense of closure and brings the progression back to the tonal center, creating a satisfying and complete harmonic resolution.

So, while the use of a major chord on the supertonic degree can seem unusual at first glance, it can effectively create a sense of contrast and tension within a song's harmonic progression, ultimately contributing to the overall musical experience and adding depth and complexity to the music.