Also known as pizza bianca, white pizza is a variety of pizza that is made without tomato sauce, either by leaving the sauce out entirely or by replacing the sauce with a white cream and cheese sauce (not white sauce, which is something else). It frequently contains large amounts of different varieties of cheeses (ricotta, mozzarella, provolone, and parmesan), is oilier than regular pizza thanks to olive oil, and is heavily seasoned with garlic and other herbs in an effort to replace the large amount of flavor lost to the lack of tomato sauce.
White pizzas accept toppings the same as other pizzas, but typically do not pair well with heavily seasoned meats like pepperoni and sausage. In my experience, I have had white pizza that contains nothing but the above ingredients; white pizza with onions; white pizza with diced tomatoes; and white pizza with broccoli, onions, and chicken.
Because it is cheesier and oilier than regular pizza, white pizza is very high in fat and makes a very satisfying meal. Additionally, many people find it to be quite delicious, owing to the fact that it is fundamentally a heavily seasoned cheese bread. Depending on your local restaurant's recipe, it may be more or less like regular pizza, but it is almost certain to be delicious. It's just as certain to be bad for you, so enjoy in moderation, please!