Question: Is it permissible to invoke Allaah saying “Yaa Hoo” i.e. referring to Allaah with He meaning: “He is Allaah”?
Answer: Single pronouns refer to the speaker, the addressee or the absent. They are not names of Allaah in the lingual or the Shar`ee meaning because He does not name Himself by it. So, invoking Him with them is nomination, calling and mentioning Him with anything other than His names which is not permissible… read more here.