Change name in URL

Hi,
To add screenshots to this thread please use an image host such as https://postimages.org/ and then post the links.
For your question about “Tags”, I took a look at both of your links and the first one has the word “Tags” in the post (screenshot 1) and the second link has the word “Tag” in the URL (screenshot 2)
So I assume that you would like the word “Nøgleord” to replace both?

For the first one, Try adding this code to the end of your functions.php file in Appearance > Editor:

function custom_tag_script(){
  ?>
  <script>
(function($){
  $(document).ready(function(){
  $('.blog-tags.minor-meta strong').each(function() {
    var text = $(this).text();
    $(this).text(text.replace('Tags', 'Nøgleord')); 
});
});
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'custom_tag_script');

Please see the screenshot 3 in Private Content area.

For the second one, the word “Tag” can be changed at WordPress > Settings > Permalink Settings > Tag base

then the URL is changed:

Please let me know if I understood correctly.

Best regards,
Mike