There are three types of grain medium, soft, and hard. All the flour which comes from these grains have gluten. Now you are thinking what is gluten? I am not describing it technically but gluten is a thing like a chewing gum. Soft grains create ordinary ones but hard grains create big bubble gums. So if you are thinking about baking cake, pastry, biscuits, etc. what you need is flour from soft grains but for making bread you will need flour from hard grain.
The quality of the flour is determined while milling. It is crushed in either modern automatic rollers or traditional millstones. There are three components which makes a grain the white starchy endosperm, the protective layers of outer casing called bran, and the germ. The germ contains vitamins, oils, and protein.
The whole wheat grains are grounded as flours and they are called whole meal. The white powdery part is called flour which is separated from bran and germ. But one thing is for sure that by removing the bran and germ is removing a lot of goodness from the flour. I will suggest to keep both as they have very important nutrients for our body like dietary fiber, minerals (manganese and iron), and vitamins (vitamin B6 and niacin). Lastly just keep in mind that bread and pizzas need flour from hard grains and cake, pastry need it from soft grains.
So now I hope you had understood about the different types of flours and where to use them. Some of you will say that you need high protein flour to maintain a balanced diet. I will suggest you to visit this link and you will find the most health efficient flour there which will suit your need and you will be able to get the desired result you want.