hr.report.xml
<?xml version="1.0"?>
<odoo>
<report
id="action_report_holidayssummary"
string="Cost Recovery"
model="hhd.cost.recovery"
report_type="qweb-pdf"
name="hhd_cost_recovery.report_session_view"
file="hhd_cost_recovery.report_session"
menu="False"/>
<record id="action_report_holidayssummary" model="ir.actions.report">
<field name="paperformat_id" ref="hr_holidays.paperformat_hrsummary"/>
</record>
</odoo>
hr_template.xml
hr_template.xml
<?xml version="1.0" encoding="utf-8"?>
<odoo>
<template id="report_session_view">
<t t-call="web.html_container">
<t t-foreach="docs" t-as="doc">
<t t-call="web.external_layout">
<div class="page">
<h2 t-field="doc.name"/>
<p>From <span t-field="doc.date_from"/> to <span t-field="doc.date_to "/></p>
<h3>Customer:</h3>
<ul>
<t t-foreach="doc.employee_id" t-as="employee">
<li><span t-field="employee .name"/></li>
</t>
</ul>
</div>
</t>
</t>
</t>
</template>
</odoo>
See this: https://www.youtube.com/watch?v=SkKAXURqNfQ&list=PLqRRLx0cl0hqclwqsT4cm8vkIU4NAj3uA