add currency switcher in shopify theme

header.liquid

{% form 'currency' %}
        <select name="currency">
         {% for currency in shop.enabled_currencies %}
             {% if currency == cart.currency %}
             <option selected="true">{{currency.iso_code}} {{currency.symbol}}</option>
             {% else %}
             <option>{{currency.iso_code}}</option>
            {% endif %}
          {% endfor %}
           </select>
       {% endform %}