Code 1 :

class SaleOrderInherit(models.Model):
"""Inherited IrConfigSettings for website first sale order discount"""
_inherit = 'sale.order'

customer_info = fields.Html(string="Customer Info")

Code 2 :

<record id="sale_order_inherited_view_form" model="ir.ui.view">
<field name="name">sale.order.inherited.form</field>
<field name="model">sale.order</field>
<field name="inherit_id" ref="sale.view_order_form"/>
<field name="arch" type="xml">
<xpath expr="//field[@name='signed_by']" position="after">
<field name="customer_info" widget="html"/>
</xpath>
</field>
</record>

Code 3 :

<!-- report action -->
<record id="action_report_product_product" model="ir.actions.report">
<field name="name">Sale Order</field>
<field name="model">sale.order</field>
<field name="report_type">qweb-pdf</field>
<field name="report_name">website_first_order_discount.report_product</field>
<field name="report_file">website_first_order_discount.report_product</field>
<field name="binding_model_id" ref="sale.model_sale_order"/>
<field name="binding_type">report</field>
</record>

<!-- Report Template -->
<template id="report_product">
<t t-call="web.html_container">
<t t-foreach="docs" t-as="o">
<t t-call="web.external_layout">
<div class="page">
<div class="oe_structure"/>
<h2>Product Report</h2>
<p><span t-field="o.customer_info"/></p>
</div>
</t>
</t>
</t>
</template>