ems-sample-plugin

<?php
/*
Plugin Name: Emergency Broadcast System
Author: Everyone
*/

function ebs_header_message() {
   
   echo '<div style="background:red;color:white">THIS IS BAD. COME BACK LATER</div>';

}

add_action('wp_head', 'ebs_header_message');

function ebs_content_message($content) {

   $content .= 'Things are bad - Josh';

   return $content;
}
add_filter('the_content', 'ebs_content_message');