The melody of Happy Birthday by Stevie Wonder runs 353 notes across 52 bars, 4:17 long in C at 100 beats per minute. The tab sits low on the neck, mostly under the fourth fret, 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 Birthday chords and lyrics.