Odoo-Build/snippets/stock.report_delivery_document.set_customer_reference.xml

<?xml version="1.0"?>
<data inherit_id="stock.report_delivery_document" priority="50">

  <xpath expr="//t[@t-set='address']" position="before">
    <t t-set="information_block">
      <span><strong>Kundennummer: </strong></span>
      <span t-esc="partner.ref"/>
      <br/>
      <br/>
    </t>
  </xpath>

</data>