How many groups are angels divided into? What are their duties?
Only Allah knows the number of angels. There is no clear information about the number of angels in the Qur’an and hadiths. However, it is possible for us to say that they are far more than we can count based upon hadiths. Moreover, according to the news given by the prophet Muhammad (PBUH); an angel comes to the earth with a drop of rain and its turn does not come again. We can range the famous angels and their duties as follows;
Gabriel (PBUH): The Archangel (A.S)
Gabriel (A.S) is one of the four greatest angels. He is appointed to convey revelations to the prophets by Allah. In three places of the Qur’an, His name is Jibril. Besides, He is mentioned in verses as the spirit, rasulun karim, ruh al-Amin and ruh al-qudus”. In addition to these, in one of the hadiths, he is called “an-namus”.

The Angel of Soor (The Trumpet): Hz. Israfel (A.S)
The angel that will blow the trumpet is called Israfel. His name is mentioned among the four great angels in the hadiths. Israfel will blow two times, in the first one, the Doomsday will occur and in the second blowing, the resurrection will occur. Because of this duty of him, He is called the angel of Soor (the Trumpet). When the prophet Muhammad (PBUH) was asked about the nature of the trumpet, he answered: “A horn that is blown” (Ahmad b. Hanbal, II, 196).
The prophet Muhammad (PBUH) said that “Israfel is awaiting the order of blowing while He grasps the trumpet”. (Tabari Jami-ul Bayan, VII, 211; Ibn Kathir, Tafsiru’l-Qur’an-il Azim, Egypt, n.d. II, 276)
The Angel of Death: Hz. Azrael (A.S)
His duty is to grasp the souls of people whose death times have come. He is called as “Malak-ul Mawt”, that is, the angel of death.
Say:"The Angel of Death, put in charge of you, will (duly) take your souls: then shall ye be brought back to your Lord."(Surah as-Sajda)

The Angel that controls the events in this realm: Hz. Mikail (A.S) (Michael)
He is one of the greatest angels of four and He is responsible for the pouring of rain, the blowing of the wind, natural events such as the ordering of seasons and the management of supplications of the created beings. He is only mentioned in one place of the Qur’an. Hz. Mikail is the angel that manages the divine work of arts that are planted on the field of earth with the power of Allah and His order.
The angels of Kiraman Katibin
It is the names of the angels who are attendant on the right and left of humans. The angel on the right is responsible for recording the good deeds and manners; the angel on the left is responsible for recording the bad deeds and manners. “The angels who are also called Hafaza will attend as witnesses of the deeds of humans in the Day of Judgment during reckoning.

The Angels of Muqarrabun
The angels who are known asIlliyyun and Karubbiyyun are responsible for glorifying Allah, are very close to Him and have an exalted place before Allah.
“Those who sustain the Throne (of Allah) and those around it sing Glory and Praise to their Lord; believe in Him; and implore forgiveness for those who believe.”(Surah Ghafir, 7)
Munkar - Nakir Angels:
They are the angels that question man after he dies in the grave. The words of “Munkar” and “Nakir” means unknown, unrecognized and unaccustomed. They are called by this way because they come to the dead in a way that he/she has not seen before. These two angels question the dead by questions as follows and treat them according to the answers that they receive: Who is your lord? Who is your prophet? What is your book?
There are more angels than mentioned here. In hadiths, there are angels who inspires man the right and truth, descend on the earth when the Qur’an is recited, who are spiritual herders of animals on earth, who manage clouds