Basically, this is a custom HTML module with some additional options so I'm afraid that it will still requires some basic knowledge about HTML
domir21 We added a horizontal line, but the text is displayed without it.
I got your point but this Articles Category module in Joomla doesn't support to show that HTML tags in the introtext section in this module. You can test this module in Joomla default template like Cassiopeia and see the same.