Mozzarella Cheese that originated from Italy is usually made from water buffalos milk that is herded in very few countries such as Italy and Bulgaria.
However the Mozzarella Cheese Made in the USA is usually made from Cow milk and not goats milk.
Some people do find that goat cheese and Mozzarella Cheese taste nearly the same but Mozzarella Cheese and Goat Cheese are different unless you actually make the Mozzarella Cheese from some goats milk to make goat milk mozzarella cheese.
But the mozzarella cheese you buy in the grocery stores in the USA is almost always made from cow milk and not goats milk or buffalo milk.