Too often the baking newbie is inundated by terms, terminology, and definitions that lack any useful metric. Since this isn't a general education essay, I'm only going to focus on the flour that I use. My primary baking focus is on sourdough breads. And to that end I use and/or recommend these flours:
Bread Flour [BF] - a specific, high-protein flour specifically formulated for bread by including barley malt and sometimes other conditioners. This flour will make excellent bread, but makes other things (biscuits, cakes, pies, etc) too tough for my liking.
Gold Medal ® "Harvest
King" [HK] - an unbleached all purpose flour specifically crafted for bread.
I now use this most excellent flour exclusively for my breads. Nothing else I've ever used even comes close!
Whole Wheat flour [WW] - The whole wheat berry. This flour will make a hearty, nutty, brownish bread. It won't rise as high, and will be both sweeter and chewier. Although you can make 100% WW breads, because of its inability to rise as high as white flour, it is most often mixed with white flour.
Dark Rye flour - Made from rye berries. This flour imparts the distinctive "Rye" flavor and is prized by many--like me--that like northern European breads.
DUrum flour [DU]- Made from the Durum wheat berry, it is usually sold (or found, in the USofA at least) as "Semolina" or pasta flour. This flour is a bit more yellowish and rougher than regular bread flour. I love the flavor and smooth texture it brings to the bread. While you can use it anyplace you like, it is most often used in high-hydration Italian breads.
There are many more kinds of flours, but I've left them off as they're beyond the pale of this short note. I use the ones listed above, and by varying the ratios of them in the dough (and the water), you'll change the result into the many different varieties of bread that are made. If you want more details, go here.