Meitar

Make your site’s on-screen admin help tabs more helpful by adding custom help tabs or additional sidebar content to any screen of the WordPress Admin Dashboard’s built-in “Help” menu simply by placing help files in a special folder.
This plugin looks for files located in your current theme’s <code>admin-help/</code> folder and, based on their name, adds their content to the WordPress on-screen help menuing system. The files should be written in <a href="https://daringfireball.net/projects/markdown/" rel="nofollow ugc">markdown</a>.
You can augment any screen’s help tabs or help sidebar, including screens created by other plugins. The name of the help file determines which screen in the WordPress admin area the file’s content will be added to.
You can add help content in any language, and the plugin will automatically load the correct language file for your site. This makes translating help content easy.
For instance, if you run an English website and want to augment the built-in help provided by WordPress core or a custom plugin shown on the user’s profile editing page, add a file at <code>YOUR_THEME/admin-help/en_US/profile.md</code>, where <code>YOUR_THEME</code> is the theme folder. (For a Spanish site, add a file to <code>YOUR_THEME/admin-help/es_ES/profile.md</code>.)
The rules used by the plugin to determine which file to load on which screen are as follows:
<ul>
<li>Each help file is contained within a directory matching the <a href="https://developer.wordpress.org/reference/functions/get_locale/" rel="nofollow ugc">locale string of the WordPress installation</a>. Control the locale string by changing the WordPress language setting.</li>
<li>File names reference the <code>$action</code> and <code>$id</code> members of the <a href="https://developer.wordpress.org/reference/classes/wp_screen/" rel="nofollow ugc"><code>WP_Screen</code></a> class.</li>
<li>Files can be optionally suffixed with a numeric priority (lower numbers display first, above the content of files with larger numbers as per <code>WP_Screen</code> documentation).</li>
<li>Files can be optionally prefixed with <code>sidebar-</code> indicating that the file contains content intended for the help sidebar rather than a tab of its own.</li>
<li>The special filename <code>sidebar.md</code> is appended to the sidebar on every WordPress admin screen page where on-screen help is shown.</li>
</ul>
For plugin or theme authors
To use WP Screen Help Loader in your plugin, all you need to do is:
<pre><code>function my_plugin_add_custom_help () {
 new WP_Screen_Help_Loader(plugin_dir_path(__FILE__) . 'help');
}
add_action('admin_head', 'my_plugin_add_custom_help');
</code></pre>
Now put your localized help contents into the <code>help/YOUR_LANGUAGE</code> directory in your plugin directory. That’s it! 
If you like this plugin, please consider <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=TJLPJYXHSRBEE&lc=US&item_name=WP%20Screen%20Help%20Loader&item_number=wp-screen-help-loader&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donate_SM%2egif%3aNonHosted" rel="nofollow ugc">making a donation</a> for your use of the plugin, <a href="http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2Fs%3Fie%3DUTF8%26redirect%3Dtrue%26sort%3Drelevancerank%26search-type%3Dss%26index%3Dbooks%26ref%3Dntt%255Fathr%255Fdp%255Fsr%255F2%26field-author%3DMeitar%2520Moscovitz&tag=maymaydotnet-20&linkCode=ur2&camp=1789&creative=390957" rel="nofollow ugc">purchasing one of Meitar’s web development books</a> or, better yet, contributing directly to <a href="http://Cyberbusking.org/" rel="nofollow ugc">Meitar’s Cyberbusking fund</a>. (Publishing royalties ain’t exactly the lucrative income it used to be, y’know?) Your support is appreciated!

WP Screen Help Loader

Easily add custom on-screen help to the admin area of your WordPress website.

Tyler Steinhaus

A very lightweight plugin that adds a metabox onto the add/edit screen for any post type (besides attachment, revision, and nav_menu_item) that allows you to quickly switch between other posts in the post type without having to go back to view all posts.

Quick Post Change

This plugin gives you a dropdown to quickly change which post you are editing in the admin panel.

WP Screen Help Loader vs Quick Post Change