The melody of Happy Days by Pratt & McClain runs 134 notes across 35 bars, 1:05 long in Bb at 150 beats per minute. The tab sits almost entirely in the first two frets, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? Happy Days chords and lyrics.