Remove unwanted text and URL from WordPress comment form http://www.wppicker.com/10-quick-settings-to-reduce-spam-comments-on-wordpress/

remove-comment-form-url.php

//* Remove Comment Form Website URL Field
add_filter('comment_form_default_fields','wpp_remove_comment_url');
function wpp_remove_comment_url($fields) { 
    unset($fields['url']);
    return $fields;
}

//* Remove comment form allowed tags
add_filter( 'comment_form_defaults', 'wpp_remove_comment_form_allowed_tags' );
function wpp_remove_comment_form_allowed_tags( $defaults ) {
    $defaults['comment_notes_after'] = '';
		$defaults['comment_notes_before'] = '';
	return $defaults;
}