Hi,

You need to adjust the paper size format, such as the page height and width:

Using the Odoo Interface:

Go to Settings → Technical → Reports and Locate the report you want to modify. Check the "Paper Format" field associated with the report.

Edit the existing paper format or create a new one. You can customize settings such as paper size, margins, and orientation.

Using XML Code:

You can define a custom paper format and associate it with a specific report by adding the following XML code in your module:

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

<odoo>

    <record id="custom_paperformat_small_footer" model="report.paperformat">

        <field name="name">Custom Small Footer Format</field>

        <field name="default" eval="False"/>

        <field name="format">custom</field>

        <field name="page_height">150</field>  

        <field name="page_width">60</field>

        <field name="margin_top">5</field>  

        <field name="margin_bottom">5</field>

        <field name="header_spacing">5</field>

        <field name="orientation">Portrait</field>

        <field name="dpi">90</field>

    </record>

    <!-- Link the new paperformat to a specific report -->

    <record id="your_module_report_action" model="ir.actions.report">

        <field name="paperformat_id" ref="custom_paperformat_small_footer"/>

    </record>

</odoo>

Replace your_module_report_action with the actual report action ID. Adjust the page_height, page_width, and margins according to your needs. After adding or modifying the XML, upgrade your module for the changes to take effect

Hope it helps