Why isn't my Klaviyo subscribers list syncing with Shopify customers list?

[Sandra45MJ]

Hello,

So I was told by Klaviyo customer service that I'm missing the proper tagging that is necessary for Klaviyo to sync with the Shopify customers list. Then I was given instructions that were basically Chinese to me, as they involved embedded codes and inserting a code into footer.liquid in a place that I could not find.

I was told to insert the following piece of code which looks like this:<input type="hidden" name="contact[tags]" value="newsletter">

in order to get this:
{% form 'storefront_password' %}
{{ form.errors | default_errors }}
<label for="password">Enter store using password:</label>
<input type="password" name="password" id="password" autofocus="" />
<input class="btn" name="commit" type="submit" value="Enter" />
{% endform %}

However, I am not able to find any part of this code in my footer.liquid.

Please help!