how to use wordpress template methods (like get_header()) in an additional php f

i want to add a php file and use wordpress template methods (like get_header()) in an additional php file in my website (for example in https://site.com/wordpress/myfile.php),
which files of wp-includes folder must include?

i tried to include below files but receive error “
Fatal error: Call to a member function get() on a non-object in ***\wp-includes\cache.php on line 93
“

include(‘wp-includes/functions.php’);
include(‘wp-includes/cache.php’);
include(‘wp-includes/l10n.php’);
include(‘wp-includes/plugin.php’);
include(‘wp-includes/general-template.php’);

any idea?