I acknowledge that Michael started to sing when he was 5, but don't know what was the first song he sang on stage with Jackson 5?

At age 5, MJ did not create any new songs yet. The first song recorded দ্বারা Michael was "My Girl" দ্বারা the temptations. Michael was known for his covering of সঙ্গীত when he was a child. He did not start to become world known until age 10 when he sang "The প্রণয় আপনি save, I want আপনি back, abc, ill be there, etc."