Computer are used widely for storage of data. Like us, computers have memories too. And their memories, are called storage which are used to store data information. There are two type of storage in a computer, primary storage and seconday storage.
Primary storage is where the computer holds data that it is currently using. This place also also known as computer memory or temporary storage. For example, you tell your computer to store two numbers after processing it for addition. The computer will get these two numbers from specified location in its memory. After the A/LU adds the two number, the result will be stored to another location in the memory.
Secondary is used to store permanent data. For example, you are working on a word document and are working on it tomorrow. You cannot store the word document in the primary storage because primary storage is also known as temporary storage. The word document will be lost if you turn off the computer and so, the word document had to be saved in the secondary storage which separates from the CPU.