A typical program uses various values that may change during its execution. For Example, a program that performs some operations on the values entered by the user. The values entered by one user may differ from those entered by another user. 

Hence this makes it necessary to use variables as another user may not use the same values. When a user enters a new value that will be used in the process of operation, can store temporarily in the Random Access Memory of the computer and these values in this part of memory vary throughout the execution and hence another term for this came which is known as Variables. 

So basically, a Variable is a placeholder of the information which can be changed at runtime. And variables allow to Retrieve and Manipulate the stored information.

Variables In GO : https://www.geeksforgeeks.org/go-variables/