"The Lord God formed man out of the clay of the ground and blew into his nostrils the breath of life, and so man became a living being." (Gn 2:7)
a) The Biblical author uses figurative language " breath of life" to indicate God's direct creation of the soul.
b) The bible also tells us that God created man and woman in his own image. In what ways is "man" the image of God? Like God, the soul is living and immaterial, endowed with intelligence and free will and destined to live forever.
Scientific evolution sees the emergence of man from the animal kingdom - life forms developed slowly over millions of years, becoming more and more human-like until a creature appeared with intelligence and free will. Here we must pause and note that the higher powers of intelligence and free will could not be produced by lower bodily forms but were directly infused by God.