Gregg

This plugin allows you to change the footer text on the bottom left of the admin page.
Once activated, navigate to the Settings -> nuAdmin Footer and change the Footer text/HTML. You can use html to link to your website, your help desk, your email or anything you would like. If you find the plugin to be useful and would like to donate, you can do so in the Settings.
Here’s a link to <a href="http://www.tripleginteractive.com/blog/wordpress/custom-admin-footer/" title="free wordpress plugin: custom admin footer" rel="nofollow ugc">the blog post on this topic</a> for more information. Future version’s will have much more capabilities.

nuAdmin Footer

This plugin allows you to change the footer text on the bottom left of the admin page.

Adnan

WPBrigade

Muhammad Irfan

WP Headers and Footers plugin helps you to insert code to your WordPress website headers and footers section like Google Analytics tracking code, Facebook Pixels code, Google Optimize code for A/B testing, Custom CSS code, and more. You don’t need to edit the theme files to insert the code.
The simple interface of this plugin allows you to add code and different scripts from one place to your WordPress website (Headers, Footers, and Body section).
Features
<ul>
<li>Insert code to your WordPress headers & Footers</li>
<li>Insert Google Analytics Code to any WordPress theme</li>
<li>Insert Facebook Pixels Code</li>
<li>Add Google Optimize Code for A/B testing ( Ab Testing )</li>
<li>Add Google search console authentication code to any theme for verification</li>
<li>Add Custom CSS, any script, and HTML to your website 
Google Tag Manager code/script insertion</li>
<li>You can also insert code to your website body section 
Can add Bing webmaster tool code for website verification 
Add Google AdSense code</li>
</ul>
If you find our plugin useful, please leave a good rating/review and check our other plugins.
<ul>
<li><a href="https://analytify.io/ref/73/?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Analytify – Google Analytics Plugin</a></li>
<li><a href="https://loginpress.pro/" rel="nofollow ugc">LoginPress</a> – For Custom login page and login page security</li>
<li><a href="https://simplesocialbuttons.com?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Simple Social Buttons</a> – Plugin for Social share buttons and social icons</li>
<li><a href="https://wordpress.org/plugins/related-posts-thumbnails/">Related Posts Thumbnails Plugin</a> – For related posts/products</li>
<li><a href="http://wpbrigade.com/recommend/maintenance-mode?utm_source=wp-headers-and-footers&utm_medium=readme&utm_campaign=pro-upgrade" rel="nofollow ugc">Under Construction, Coming Soon & Maintenance Mode</a> – Plugin for Under construction & Coming soon page</li>
</ul>

Insert Headers And Footers

I like its simple design which doesn't add menu item on top level of WP admin menu. Recommended for client works and who prefer to keep WP admin menu simple. I hope you continue its simple style than adding functionalities.

Simple UI

Include inline javascript, stylesheets, CSS code or anything you want in Header and Footer areas of your WordPress with ease.

nuAdmin Footer vs Insert Headers And Footers