Angels feature in the three Abrahamic religions, they have a supporting role to God. Angels were created by God, they live in Heaven and do God's bidding. Angels have Supernatural power but aren't as powerful as God. In earlier sections of the Old Testament God tends to do his own work while in later parts of the Old Testament God becomes a more remote being sending angels to do his work. This suggests changes in the way God was seen.
In art angels are traditionally drawn as human beings with with wings like birds on their backs.