Where do we use $output and what is the purpose?

Question

can anyone explain in detail?

Answer 1

What you have asked is, "where do we use this variable, and what for". In PHP, variables are declared with the $ sign, so:

$this_is_output = "Name your variable anything, but it must conform to declaration standards. Letter or underscore to start, and numbers";

echo $this_is_output;

That will show what's contained within the variable.