This is the programming aspect of computers. Software represents the instructions that can be programmed into the hardware of the CPU for example.
A particular programming language is used to convert to another level of computing language called machine code that then is able to interact directly with the electronics of a CPU.
There are different levels of computer programming. The CPU actually only really understands only something called machine code, which is specific to design of that CPU, it gets the data in the form of strings of electrical signals that either on or off or I or O.