In making noodles, the type of flour commonly used is wheat flour. Specifically, it is usually made from wheat durum or wheat semolina, which is a hard wheat variety that has a high protein content. This type of flour gives noodles their characteristic texture, firmness, and ability to hold their shape when cooked. In some cases, all-purpose wheat flour or a combination of all-purpose flour and semolina may be used, depending on the desired texture and regional preferences.
However, it's worth noting that there are various types of noodles around the world, and different cultures may use different types of flour to make their traditional noodle varieties. For instance, in Asian cuisine, rice flour and rice starch are commonly used to make rice noodles, while buckwheat flour is used in making Japanese soba noodles. Nonetheless, wheat flour is the most widely used type for making many popular noodle varieties like spaghetti, fettuccine, and ramen.