WordPress – Alter the_content(); function

To add some content to your post body, add the following to your functions.php file:

/** Alter the content */
function add_some_content($content) {
 	$content .= 'The new content';
 	return $content;
}
add_filter( 'the_content', 'add_some_content', -9999 );Code language: PHP (php)