Q. 1. What is the Catholic Church teaching on the matter of appropriate Christmas Carols during the Christmas Season?
A. 1. Your question has two answers, depending on what you are really asking.
If you are referring to the celebration of the Holy Mass, the Catholic Church teaches that the Christmas Carols must be appropriate to reflect the coming and birth of Christ. So singing "Jingle Bell" at Mass would not be appropriate, nor is that song approved.
As for what you sing at home, at work or at your social club, you are free to sing any of the popular secular Christmas songs such as "Frosty the Snowman” or "Silent Night".