Angels are created from Noor (light). Almighty Allah has blessed them with the ability to take whatever form they wish. They sometimes come in the form of humans and sometimes in other forms.
Aqida: They do only that which is the command of Allah. They do not act contrary to the command of Allah either intentionally, unintentionally or by error. They are the Masoom servants of Allah. They are free from all major and minor sins.
Aqida: They have been given various duties. Some of them take revelation to the Prophets, some of them are responsible for causing rain, some of them are in charge of the wind, some of them are in charge of delivering sustenance, some of them are responsible for molding the form of the child in the womb of the mother, some are responsible for possessions in the human body, some protect humans against their enemies, some of them are responsible for looking for gatherings of those who make Zikr and to present themselves in it, some write the deeds of the humans, many of them have the responsibility of being present in the Darbaar of the Holy Prophet (sallal laahu alaihi wasallam), some of them are given the duty of carrying the Salutations of the people to the Court of the Prophet (sallal laahu alaihi wasallam), some are responsible for questioning the dead, removing the soul, giving punishment and blowing the Soor (Horn shaped instrument on the Day of Qiyaamat). With the exception of these duties, there are various other duties given to the Angels.
Aqida: Angels are neither male nor female.
Aqida: To accept them to be Qadeem (uncreated) or say them to be the Creator is Kufr.
Aqida: Their number is only known to Him who created them (Allah), and through his informing, His Prophet (sallal laahu alaihi wasallam) knows. Four Angels are most famous: Hazrat Jibraeel, Mikaeel, Israfeel and Izraeel (alaihimus salaam). They are superior over all the other Angels.
Aqida: The slightest disrespect towards any Angel is Kufr. Some ignorant people have the habit of referring to their enemies as Malakul Mout (Angel of Death) or Izraeel. These are close to words of Kufr.
Aqida: To reject the existence of Angels by saying that Angels only refer to the power of good and nothing else is wrong. These are words of Kufr.