This question has been previously asked and answered. Please see the links below.
The chorus in Antigone and other Greek plays functions as a device to keep the audience informed of the action, to influence their thinking, to comment on the action and to set the mood and tone of the particular episode of the play. In traditional Greek Theatre the chorus sang and danced and were always male. They could have up to 50 actors in a chorus, although they numbers were often less, depending on the playwright. In contemporary productions directors often have smaller numbers and mixed gender, although it is important to justify your numbering and gender selection in an essay.
they play as a conscience.