Is Iblis (Satan) one of the Jinn (creatures created from fire) or one of the angels?
Iblis is one of the Jinn, not the angels, as Allah says,
And (remember) when We said to the angels: "Prostrate yourselves unto Adam." So they prostrated themselves except Iblîs (Satan). He was one of the jinn
(Surah Al-Kahf, 18: 50) Allah also says,
He created man (Adam) from sounding clay like the clay of pottery.
And the jinn: He created from a smokeless flame of fire.
(Surah Al-Rahman, 55: 14-15) The Prophet (peace be upon him) said,
The angels were created out of light; Iblis was created out of a spark of fire; and Adam was created as he has been defined (in the Qur'an) for you.
Al-Hasan Al-Basry said that Iblis had never been an angel; he is the father of Jinn just as Adam is the father of human beings.
Ibn Jarir with an authentic Isnad (chain of narration).
However, Iblis disobeyed the orders, as he was with the angels and imitated them in their 'Ibadah (worship), so he was included in the address directed to them and disobeyed Allah's order of Sujud (Prostration).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.