3) In 'order_receipt.xml' file add below code snippet.

<?xml version="1.0" encoding="UTF-8"?>
<templates id="template" xml:space="preserve">
<t t-name="your_module_name.OrderReceipt" t-inherit="point_of_sale.OrderReceipt" t-inherit-mode="extension">
<xpath expr="//div[hasclass('paymentlines')]" position="inside">
<t t-if="props.data.session">
<h4>Session Name : <t t-esc="props.data.session"/></h4>
</t>
</xpath>
</t>
</templates>

4) In 'models.js' file add below code snippet.

/* @odoo-module */

import { Order } from "@point_of_sale/app/store/models";
import { usePos } from "@point_of_sale/app/store/pos_hook";
import { patch } from "@web/core/utils/patch";

patch(Order.prototype, {
export_for_printing() {
const result = super.export_for_printing(...arguments);
result.session = this.pos.pos_session.name;
return result;
},
});