Flour designated as "00" is ideal for pizza for a couple of reasons. For one thing, it's very finely ground--almost like talcum powder. I can feel the grit of bread flour in between my fingers but "00" feels silky smooth. It also has a lower protein, and thus lower gluten content than other flours. There are even finer flours milled--"000" and "0000"--but these tend to be lower in gluten and thus are used more for cakes and pastry. But "00" flour has enough gluten support air bubbles in the dough, but not too much, which makes pizza dough much easier to handle. The rule is, the lower the protein, the lower the gluten, which means a dough that is much less elastic.
For instance, at the other end of the spectrum, if you tried to make a pizza dough using 100% whole wheat flour, you would have a difficult time keeping your dough stretched out flat. The higher gluten makes it so elastic it would keep shrinking back smaller. (The reason why wheat pizzas are usually a mix of wheat and bread or all-purpose flours.) Using "00" flour is a dream when making pizza dough... the stuff is so supple and smooth and easy to handle.
Take the pizza pictured above... I was able to make the center of the round paper thin while the crust was nice and thick. After baking, the center was stiff enough to hold out straight when held New York style--folded at the crust. But the perimeter crust was puffy and full of air, like a light focaccia.
The sauce was simple: crushed tomatoes, red pepper flakes, basil, EVO and a tablespoon or so of sugar. The toppings were thin sliced provolone cheese, and thin-sliced Speck, a type of smoked prosciutto.
The next time you're thinking of making pizza at home, get a bag of "00" flour and give it a try. Handling such a soft, supple sough is almost an erotic experience. (I said "almost".)