Odoo-Build/snippets/account.report_invoice_document.show_weight.xml

<data inherit_id="account.report_invoice_document" priority="60">
    <xpath expr="//table[@name='invoice_line_table']//th[@name='th_quantity']" position="inside">
        <br/>
        <i>Weight</i>
    </xpath>
    <xpath expr="//table[@name='invoice_line_table']//th[@name='th_subtotal']" position="inside">
        <br/>
        <i>Total Weight</i>
    </xpath>
    <xpath expr="//table[@name='invoice_line_table']//span[@t-field='line.quantity']/.." position="inside">
        <br/>
        <i>
            <span t-field="line.product_id.weight"/>
            <span t-field="line.product_id.weight_uom_name"/>
        </i>
    </xpath>
    <xpath expr="//table[@name='invoice_line_table']//span[@t-field='line.price_subtotal']/.." position="inside">
        <br/>
        <i>
            <span t-esc="line.product_id.weight * line.quantity" t-options="{&quot;widget&quot;: &quot;float&quot;, &quot;decimal_precision&quot;: &quot;Stock Weight&quot;}"/>
            <span t-field="line.product_id.weight_uom_name"/>
        </i>
    </xpath>
</data>