Hi,

If you want to add content in the 'Order Summary' column, you can try the following approach. 

<?xml version="1.0" encoding="utf-8"?>

<odoo>

<template id="order_summary_inherit" inherit_id="website_sale.checkout_layout" name=" Order Summary Inherit">

<xpath expr="//td[@name='website_sale_cart_summary_product_name']/h6" position="after">

<!--To add something on the order line, Do your logic here. --> </xpath>

</template>

</odoo>

Hope it helps