When a person touches another person, do the atoms of the hand come into contact with the atoms of the skin of another person, or will there be a thin layer of air around all the objects that will impede the contact between the atoms of the hand and the atoms of the skin of another person? Or will almost all of the air be pushed out and there will be direct contact? thank

There is no such thing as touching when you get to the atomic level. Electrons repel each other, so at best atoms are close to each other, but quantum mechanics means the boundary of an atom isn’t well-defined. Surfaces are not infinitely flat, so there will be other atoms/molecules in there.