The white spot visible on the yolk when you crack open an egg is completely natural and usually indicates one of two things:

Chalaza
You will often notice white, spirally twisted “threads” or spots on the sides of the yolk.
What it is: This is the chalaza—an elongated strand of egg white that acts as an anchor. Its function is to hold the yolk in the center of the egg so it doesn’t bump against the shell.

What it means: A distinct, firm chalaza is evidence that the egg is very fresh. As the egg ages, the chalaza gradually breaks down and disappears.
Is it edible? Yes, the chalaza is completely harmless and edible. In most cases, it dissolves during cooking or baking.

Germinal disc (blastodisc)
If you see a small, bright white, round dot right on the surface of the yolk, it is the germinal disc.
What it is: The spot from which a chicken embryo would develop if the egg were fertilized.
What it means:

If it is a small, solid white dot, the egg was not fertilized (typical of a standard supermarket egg).

If the spot is shaped like a white ring with a clear center (resembling a small bullseye), the egg was fertilized by a rooster.
Is it edible? Yes. Refrigeration immediately halts any development; therefore, the egg remains perfectly fine in terms of nutritional value and health, and is safe to eat.