What is the ruling on bequeathing ownership of the house to the wife after death, knowing that it is mortgaged and the insurance company will pay the remaining amount?

A will in favor of an heir is not permissible, due to the Prophet's (PBUH) saying: "Indeed, Allah has given every rightful person his due right, so there is no will for an heir." Accordingly, it is not permissible for you to bequeath the house to your wife. Rather, the house and other parts of the inheritance are to be divided among the heirs according to Islamic law. Your wife receives one-eighth if you have children, or one-quarter if you do not.