If you don't need just don't pass them because passing parameters depends on what your function want to be doing with those data passed.
to go along with what shabbir stated, unless you're in the habit of using global variables, you need some mechanism to access a variable's value outside of the scope in which it was declared. The way to do that is to pass a variable as a parameter into a function.
Argument is a value either in form of integer or string which passes when a function called. It is not necessary to pass argument because it depends on a function which you define. It also depends on your program logic.
