syntax: 

  function functionname( $arg1, $arg2) {

   // some statements goes here

  }

  function functionname($arg1, $arg2='Bob'){

    // some statements goes here

    return $somevalues;

  }

Other things to know

returns numeric format 

    example code : return number_format($total, 2);

returns an Array 

    ex.: 

    function some_function() {

             return array('val1', 'val2');

    }

    list ($var1, $var2) = some_function();

global variables 

    global variables are access from with-in a function via the key word global plus(+) the actual variable name to be accessed

    ex.: 

        function someglobal() {

              global $total;

              . . .

              . .

        }