Code to “noindex” All Tag Archives in WordPress

/* No Index All Categories */
add_action('wp_head', 'wpflt_header_function_condition_noindex_all_tags');
function wpflt_header_function_condition_noindex_all_tags(){
if ( is_tag() ) { ?>
<meta name="robots" content="noindex" />
<?php }
}

This code will add ‘noindex’ metatag to the header of all Tag pages in WordPress and none of the Tag pages will be indexed.