Jonathan Bardo

Note: This plugin only works with WordPress 4.2 or higher
This plugin will enable the site administrator to easily create an admin message present on all pages. The admin has the option to let the user dismiss the message for the duration of his session.

Admin User Message

I love to use it when a website is migrated over to a new host and the DNS propagation may take a lot to be updated. Editors need to know they should stop publishing for a while :)



Useful

This does just what I want. Thanks for making it. :)
It's definitely better than https://wordpress.org/plugins/admin-screen-messages
You might want to also tag it as:
https://wordpress.org/plugins/tags/admin-message



Perfect

Add message to users of your site. Choose wheter they can dismiss it or not.

boostetonwp

BTW Contact Forms is a plugin that lets you easily create and manage your contact forms (Customer support, quote requests, lead generation, recruitment, appointment scheduling, feedback and reviews, reporting or moderation, partnerships and collaborations, internal support (extranet / intranet)).
No complicated settings, no HTML or CSS code to manage. You simply choose the position and type of fields you want to include in your forms. 
That’s it! 
They then integrate seamlessly into your theme.
When your customers contact you, you receive an email and a message that can be viewed directly from your site’s administration panel. 
No risk of missing a message!
<h3>License</h3>
This plugin is licensed under the GPLv2 or later.

BTW Contact Forms

Create contact forms easily with automatic layout and no code required.

Admin User Message vs BTW Contact Forms