post-edit-reminder.php

<?php
/*
Plugin Name: Post Edit Reminder
Description: Allows admin to add a customizable post-it-like reminder to Post Edit screen. Requires Advanced Custom Fields
Author: Joe Bacal
Version: 0.1
*/

function postreminder_text_after_title( $post_type ) {
  $message = get_field('post_reminder_text', 'option');
  ?>
    <div class="after-title-help postbox" style="width:50%; padding:10px; border-radius:6px; background-color:#fefece;">
      <?php echo $message; ?>
    </div><!-- .postbox -->
<?php }
add_action( 'edit_form_after_title', 'postreminder_text_after_title' );
//create the options page via acf
if( function_exists('acf_add_options_page') ) {
	acf_add_options_page(array(
		'page_title' 	=> 'post-reminder-edit',
		'menu_title'	=> 'Post Reminder Edit',
		'menu_slug' 	=> 'post-reminder-edit',
		'capability'	=> 'activate_plugins',
		'redirect'		=> false
	));
}
//local acf field group
if( function_exists('acf_add_local_field_group') ):
acf_add_local_field_group(array (
	'key' => 'group_5887a22b3c8b2',
	'title' => 'Post Reminder Text',
	'fields' => array (
		array (
			'tabs' => 'all',
			'toolbar' => 'full',
			'media_upload' => 1,
			'default_value' => '',
			'delay' => 0,
			'key' => 'field_5887a23639b61',
			'label' => 'Post Reminder Text',
			'name' => 'post_reminder_text',
			'type' => 'wysiwyg',
			'instructions' => '',
			'required' => 0,
			'conditional_logic' => 0,
			'wrapper' => array (
				'width' => '',
				'class' => '',
				'id' => '',
			),
		),
	),
	'location' => array (
		array (
			array (
				'param' => 'options_page',
				'operator' => '==',
				'value' => 'post-reminder-edit',
			),
		),
	),
	'menu_order' => 0,
	'position' => 'normal',
	'style' => 'default',
	'label_placement' => 'top',
	'instruction_placement' => 'label',
	'hide_on_screen' => '',
	'active' => 1,
	'description' => '',
));
endif;