Display product barcode number on packing slip

You can use this workaround to display product barcode on packing slips (without installing any apps). Edit your packing slip template (Settings > Shipping and Delivery > Edit Packing Slip Template) to replace the snippet that displays product SKU

{% if line_item.sku != blank %}
  
    {{ line_item.sku }}
  
{% endif %}

with the following:

{% if line_item.sku != blank %}
  {% for item in order.line_items %}
    {% if item.sku == line_item.sku %}
      
        {{ item.variant.barcode }}
      
      {% break %}
    {% endif %}
  {% endfor %}
{% endif %}

Hope this helps