In Italy, flour is categorized by the fineness of the milling rather than the protein content as in the US. The grades range from 00 (the finest) to 2 (the coarsest) with 0 and 1 in between. 00 flour is most commonly used to make breads, pizza doughnuts, and pastas as it produces doughs with great elasticity. I use this flour in this Parmesan Breadsticks recipe.
00 flour can be difficult to find and a bit pricey here in the US. Antimo Caputo is the most popular brand and used routinely in pizzerias in Italy. Thanks to the internet you can find reasonably priced 00 flour anywhere. I typically buy Antimo Caputo here.