Changing text | WordPress.org

I have checked that you are using the Astra theme. That’s not CSS but add some PHP code to change the text strings.

Add this code to the child-theme functions.php file to change the text strings.

add_filter('comment_form_defaults', 'wpastra_custom_comment_title', 20);
function wpastra_custom_comment_title( $defaults ){
  $defaults['title_reply'] = __('Leave Your Thoughts Here...', 'astra');
  return $defaults;
}

If you want to change the title tag, use this.

add_filter( 'comment_form_defaults', 'leave_a_comment_title_tag' );
function leave_a_comment_title_tag( $defaults ){
  $defaults['title_reply_before'] = '<p id="reply-title" class="comment-reply-title">';
  $defaults['title_reply_after'] = '</p>';
  return $defaults;
}

Further any Astra related, support, I would highly suggest post it here .

For a small text change like this, it may not be worth the hassle of creating AND maintaining a child theme.

In this case, a quick CSS text replacement hack should be an acceptable solution.

h3#reply-title {
   visibility: hidden;
}
h3#reply-title:before{
    visibility: visible !important;
    content: "Comments";
}