The material of coats is not clear; instead, it is dubious. The Bible translates "coats" of skin and "garments" of skin as our mortal skin and animal' skin.[4]
Symbolic
If clothes were of animal skin, the question arises, who killed the animal and what was that? These ''garments'' of skin are resolved as a symbol of salvation.[5]
Wisdom
The first man and woman didn't even know how to dress properly. Their fig-leaf aprons served no purpose. In their "shame" the first couple always found it necessary to hide themselves from God (Gen.3.8).
And they heard the sound of the Lord God walking in the garden in the cool of the day, and the man and his wife hid themselves from the presence of the Lord God among the trees of the garden.
God's creation of the "coats of skins" can thus be seen as a sign of his superior wisdom, his recognition of his people' true needs in light of their impending expulsion from the Garden.
And the LORD God made for Adam and his wife garments of skins and clothed them