Is it permissible for a man to marry a woman for whom he made a hijab (amulet/charm) to make her love him, and is this marriage and the children resulting from it forbidden or permissible?

What the man did is a type of magic called "love magic" or "tiwalah" (amulet/charm), and it is shirk (polytheism/associating partners with God). It is major shirk if the doer believes it has an effect by itself, and minor shirk if he believes that God is the cause. He must repent sincerely and destroy what he did. The wife is advised to protect herself with the prescribed adhkar (remembrances of God) without informing her.