Answer
According to the Sunni creed, Heaven and Hell have been created at this moment. However, after the Day of Judgment and the resurrection, Heaven and Hell will be filled with the substances appropriate to them. Just as a building is constructed, but it is not known beforehand who will live in it, similarly, the building of Heaven and Hell has been constructed and established. But the people and substances that will enter it will be determined later.

Heaven and Hell have been created; after the Day of Judgment, as our Master stated, «the footnotes will be written.»