[insert_php]

if( is_user_logged_in() ) {
echo ‘Download file‘;
} else {
echo “You must be logged in to download the file.”;
}

Example of executing code for the whole website (global):
remove_action(‘wp_head’, ‘wp_generator’);
remove_action(‘wp_head’, ‘rsd_link’);
remove_action( ‘wp_head’, ‘wlwmanifest_link’);
remove_action( ‘wp_head’, ‘wp_shortlink_wp_head’);

[/insert_php]