Packing Slips

Using Shopify's Default Packing Slips

Your bin locations are stored as order metafields and can be exposed using Liquid.
Go to Shopify Admin > Settings > Shipping and delivery > Edit Packing Slips
{% assign bins = order.metafields.bins %}
Look for this line of code for use with next code snippet
{% for line_item in line_items_in_shipment %}
{{bins[line_item.sku]}}