Jenst

Cookie Message plugin will on activation add a message at the bottom of your screen.
When clicking the button it will disapear. How long is for you to decide but default is forever. It will remember it by HTML5 localstorage, not by a cookie.
You have settings for information that goes into the message, colors, fonts and you can disable CSS and javascript if you need to. See screenshots for more information about the settings.

Cookie Message

EU cookie law message at the bottom of the screen.

Venugopal

*Show Urgent or Normal notice on admin dashboard area
More WordPress help please follow Me on this link 
<a href="https://venugopalphp.wordpress.com/" rel="nofollow ugc">Venugopal</a>

Show notice or message on admin area

Show Urgent or Normal notice  on admin dashboard area

Cookie Message vs Show notice or message on admin area