6.How to Import External PHP

include() Function

include () Function is used to download a PHP File in another PHP File.
Syntax:

<?php

  include("path/file_name.php");

?>

include_once() Function

include_once () Function is used to download a PHP File to put in another PHP File only one time.
Syntax:

<?php

  include_once("path/file_name.php");

?>

Require() Function

Require () is similar to include, but if the file php Error Code below does not work. And Error fatal error: if include Error warning.
Syntax:

<?php

  require("path/file_name.php");

?>

Require_once() Function

Require_once () Require (), but it literally download.
Syntax:

<?php

  require_once("path/file_name.php");

?>