Using MyBB board messages as global announcements displayed throughout your forum is a great way to get everyone’s attention, usually for MyBB this is done using plugins or modifications, but in this tutorial you can create your own MyBB board messages without running SQL queries on every page by adding a little code to your forum.
Go to Admin CP > Templates & Style > Templates > (your default template) > Header Templates > header and at the bottom of the code on the next available line add the following:
<div style="text-align: center;"><table border="0" cellspacing="0" cellpadding="4" class="tborder"><tr><td class="thead"><strong>My Board Message</strong></td></tr><tr><td class="trow1"> This is the first board message, edit me to add your announcement. </td></tr></table></div><br />
A new MyBB board messages box should appear on every page of your forum now, it uses HTML format. It’s very simple but very customizable if you know basic HTML. For example if you want to be fancy you can add different colors to the text such as highlights, example code:
<div style="text-align: center;"><table border="0" cellspacing="0" cellpadding="4" class="tborder"><tr><td class="thead"><strong>My Board Message</strong></td></tr><tr><td class="trow1"> <span style="background-color: #BAFFBF;"><strong>This is the first board message, edit me to add your announcement.</strong></span><br /> <span style="background-color: #F0FFBA;">This is the second board message, edit me to add your announcement.</span><br /> <span style="background-color: #FFBABA;">This is the third board message, edit me to add your announcement.</span> </td></tr></table></div><br />
And the result of the MyBB board messages is this:
The first line of text in the example above is using a bold tag, all are using highlight colors. Again the example is simple coding but it is customizable so you can add just about anything. Use it for MyBB board messages, as a news bar, marquee (scrolling text for announcements) and more.
If you don’t always like navigating through the Admin CP to get to the header template and make changes, just bookmark the header edit page for quick access. This MyBB board message method is similar to the MyBB sidebox code too.

great post, thanks for share
Thanks man;