pos/pos_loyalty/views/pos_order_view.xml

<?xml version="1.0"?>
<odoo>
    <record id="pos_order_form_view" model="ir.ui.view">
        <field name="name">pos.order.form</field>
        <field name="model">pos.order</field>
        <field name="inherit_id" ref="point_of_sale.view_pos_pos_form"/>
        <field name="arch" type="xml">
            <xpath expr="//page[@name='extra']" position="inside">
                <group name="loyalty" string="Loyalty Programs">
                    <field name="loyalty_points"/>
                </group>
            </xpath>
        </field>
    </record>
</odoo>