In "Tess of D'Urbervilles" the story is told with third person omniscient—meaning the narrator is outside of the story but can see and hear the thoughts and emotions of every character in the story. This has some interesting narrative benefits.

The role of this sort of narrator is to show the story from every perspective and give a deep understanding of the events of a novel and how it impacts everyone involved. In this novel, it allows everyone to see what the actions of the characters make everyone feel, and how they are all impacted. Third person omniscient is more of a rare narrative form, especially in later years, but it is used effectively here, and in similar older works, to portray a multitude of human experiences.

Thomas Hardy's Tess of the D'Urbevilles features a third person narrator (which could either be a male or a female) with an omniscient perspective. This latter fact means that the narrator is responsible for telling us the entire story, and the stories of each and everyone of the characters with complete knowledge of their thoughts and feelings. This type of narrative is often done in a sequence of events and helps frame the story by order of events. This type of narrative is also supposed to be detached, that is, that the narrator will not emit an opinion, nor judge the situation, nor the characters. 

An example of this form of storytelling goes as follows:

As the lad stood in a dubious attitude, Durbeyfield put his hand in his pocket, and produced a shilling, one of the chronically few that he possessed.

"Here's for your labour, lad."

This made a difference in the young man's estimate of the position.

"Yes, Sir John. Thank 'ee. Anything else I can do for 'ee, Sir John?"

Here we see that the narrator merely tells the tale, repeats the dialogue, but at the same time is able to tell us about the emotions of the lad, for example, and his "dubious attitude". The narrator also knows that Durbeyfield is poor, as his shilling is "one of the chronically few" that he possessed. 

However, in Tess of D'urbevilles we find that Thomas Hardy, himself, makes a couple of "appearances" (intended as a cameo, perhaps?) where he actually expresses his opinion of certain situations. This is seen as an awkward use of creative license, as we (as readers) don't really feel like judging Tess's misfortunes.

At some points the narrative gets so intense that we may not even feel like stating the obvious: that Tess's life is quite miserable. Yet, Hardy gives us a surprise personal impression during the first meeting between Tess and Angel, where he interposes that he does not remember the name of the "lucky girl" that Angel chooses to dance with, instead of Tess.

Moreover, we see how Hardy closes the story with an insightful message that makes us wonder whether he really wants the reader to hear his own opinion, or form our own, about Tess's situation. On Phase The Seventh, "Fulfillment", (ch. LIX) says Hardy as he ends his novel

"Justice" was done, and the President of the Immortals, in Aeschylean phrase, had ended his sport with Tess. And the d'Urberville knights and dames slept on in their tombs unknowing. The two speechless gazers bent themselves down to the earth, as if in prayer, and remained thus a long time, absolutely motionless: the flag continued to wave silently. As soon as they had strength, they arose, joined hands again, and went on.