The Archangels and some of the other angels whose names we know, have specific duties assigned to them.
Some Angels are in charge of Heaven and some in charge of Hell, some of looking after children, the old ,the weak and other people whom Allah wishes to protect.
All throughout the stages of our creation the angels have been there with some duty. When we were nothing in our mothers stomach, an angel was there breathing a soul into us. They are there every day reporting to Allah our Salah. They are there every second recording what we whisper and speak. When the time of our death comes they are ready to take our soul. And when the day of Judgement commences, an angel will blow the trumpet to announce it.