How to play this song ?

These are single notes, not chords.
Each note must be played individually.

There are different notations, like, A B C , DO RE MI , Sa Re Ga and numeric notation 1 2 3.
Choose one that fits better for you.

You can distinguish the octave by the color of the note and if it is UPPERCASE (high pitch) or lowercase (low pitch). Enjoy

One day in your life

Michael Jackson Pop

The original key of "One day in your life" by Michael Jackson is C major. The song was released in 1981 as a single from his album "Forever, Michael". It was written by Sam Brown III and the song's lyrics depict the emotions and longing of lost love. Interestingly, "One day in your life" became a big hit in European countries, especially in the UK where it topped the charts. The melody of the song is melodic and showcases Jackson's signature vocals.