In the purchase order printout, Odoo uses the warehouse ID by default because the template is referencing picking_type_id.warehouse_id.name instead of the warehouse’s address fields.

To print the actual warehouse address, you need to edit the Purchase Order QWeb report:

1. Activate Developer Mode

   Settings → Developer Mode

2. Go to

   Settings → Technical → User Interface → Views

3. Search for:

   report_purchaseorder_document

   (or Purchase Order QWeb template)

4. Find the part showing:

   <t t-esc="o.picking_type_id.warehouse_id"/>
   

   or something similar displaying only the ID.

5. Replace it with the warehouse address fields, for example:

   <div>
       <t t-esc="o.picking_type_id.warehouse_id.name"/><br/>
       <t t-esc="o.picking_type_id.warehouse_id.partner_id.street"/><br/>
       <t t-esc="o.picking_type_id.warehouse_id.partner_id.city"/>
       <t t-esc="o.picking_type_id.warehouse_id.partner_id.zip"/><br/>
       <t t-esc="o.picking_type_id.warehouse_id.partner_id.country_id.name"/>
   </div>
   

   Odoo stores the warehouse address on the related partner record (warehouse_id.partner_id).

6. Save → Print the purchase order again.

Now the Delivery To section will show the full warehouse address instead of the ID.