Is sponsoring an orphan from an orphanage and raising them at home permissible or forbidden?

Your desire to sponsor an orphan child to live with you is commendable in Islamic law. Islam has assigned a great reward and immense virtue to this act. The one who sponsors an orphan and takes care of their affairs—including expenses, clothing, discipline, upbringing, and so on—will be with the Prophet, peace be upon him, in Paradise. However, what is forbidden is adoption, which is attributing the orphan to someone other than their father; this is among the gravest sins. It is important to note that if the orphan reaches adolescence and is not a mahram, it is not permissible for him to be alone with the wife, nor for her to expose any part of her body in front of him. If the sponsored child is female and reaches the age of desire, it is not permissible for you to be alone with her or to look at her awrah; rather, she must be treated as a non-mahram woman.