Ahmadi Muslims believe in Angels, they are spiritual beings who act on the commands of Allah and have various duties. But many Muslims believe that Iblis was an Angel who disobeyed Allah:

And remember the time when We said to the angels, ‘Submit to Adam’, and they all submitted, but Iblis did not. He refused and was too proud; and he was of the disbelievers.

Holy Qur'an, Chapter 2, verse 35

Ahmadi Muslims do not believe that Iblis was an angel, as Angels have to obey Allah; they do not have a free will, whereas Iblis is depicted to have a free will and opposed Allah’s command. Therefore Iblis cannot be an Angel.