Can I add the line item properties on the packing slip?

If you're using the standard packing slip in Shopify, you may see the packing slip below:

The line item on the order details page:

As you can see, the individual line item properties are lost.

You can change the packing slip template in Shipping and delivery => Packing slip template => Edit. Change the liquid inside:

Steps:

1. Search for the line {% if line_item.variant_title != blank %}
2. Very likely, you will see the lines similar to this:

   {% if line_item.variant_title != blank %}
   <span class="line-item-description-line">
   {{ line_item.variant_title }}
   </span>
   {% endif %}
   

3. After the line {% endif %}, hit enter to a new line. Copy and paste the codes below:

   {% if line_item.vendor == 'BYOB' or line_item.variant_title contains "BYOB" %}
      {% for property in line_item.properties %}
        <span class="line-item-description-line">
          {{ property }}
        </span>
      {% endfor %}
   {% endif %}
   

4. If class="line-item-description-line" is different than your template, change to the class of your own
5. Hit save. Refresh the order page and generate the packing slip again. It will show the correct format

For other changes, please refer to the official guide Packing slip customizations and Packing slip variable reference