Joomla editor does not insert html code completely?

Question

CMS

Guys, you need to insert html code into the joomla page. Inserted, but the tag was not inserted, what to do? You can't throw out Joomlu)) But you need to insert the code! <i class="timeline__mark"></i>

Answer 1

And where do you insert it, into the material or do you create a separate module?