How to Remove HTML Allowed Tags Text in WordPress Comment Form?

Find where the comment_form() function is called. Usually it will be in the comments.php file of your WordPress theme.

It might be displayed like:

<?php comment_form(); ?>

Pass an argument to the function as below:

<?php comment_form(array('comment_notes_after' => '')); ?>

The array can have other arguments as well to mod the comment form to your liking. Refer to WordPress comment form codex for all possibilities.