What is the use of a static variable in C?

Following are the uses of a static variable:

A variable which is declared as static is known as a static variable. The static variable retains its value between multiple function calls.
Static variables are used because the scope of the static variable is available in the entire program. So, we can access a static variable anywhere in the program.
The static variable is initially initialized to zero. If we update the value of a variable, then the updated value is assigned.
The static variable is used as a common value which is shared by all the methods.
The static variable is initialized only once in the memory heap to reduce the memory usage.