Every disk has partitions, even if we can't see them. They are essential for storing files. If we buy a PC with Windows on board, we will probably have at least two, if not three partitions created by default. The main one is of course C: where the system is located. It is better not to touch this one, although we usually install all programs there. Depending on the disk capacity, the next partitions can be used, for example, to store media, documents or photos.