The narrator of The Canterbury Tales is introduced in the introduction as a man named Chaucer. However, this does not mean that Geoffrey Chaucer is the narrator. Rather, the poem is narrated as if the poet is telling the story. The narrator observes each of the pilgrims and reports them to the reader through his own view. This shows the point of view from this narrator is first-person. We know this because he speaks using "I".
When the pilgrims tell their stories, a different point of view is offered. This is the third-person omniscient view. This means that we are told both the thoughts and actions of the characters. When the pilgrims are telling their stories, they are being told by a narrator who is "all knowing".