If every cell has chromosome, then why are there only 46 chromosome in the human body?

There are not only 46 chromosomes in human body … there are 46 chromosomes in each human cell

Except in sexual cells which contain 23 chromosomes (each of them) to form a zygote.
46 is generally considered Because each human originates from a single cell. All other cells are just copies of that single cell. And that single original cell, the fertilized egg, the zygote, has 46 chromosomes.