Simplest way to set a string value from code behind, and use it in .aspx

Hi,
I'm working on updating UI for an existing web forms application. In the masterpage, I need to set the values of 3 strings from code behind of the pages that inherits this masterpage. I'd like to know the simplest way to set these. The html rendered from the code in the masterpage should looks like below, with the 3 bold underlined parts are the ones that I want to dynamically set value in the .aspx.cs files, since they will change from page to page; while the rest remain the same:
<div class="col-xs-12">         <h1 class="Bg"><i class="fa fa-fw fa-random"></i> System Functions / Permissions </h1> </div>
<h1>Permissions</h1>
For & ...