Hi,
If you want to remove it completely from the source (for example, if it's hardcoded), you can override the XML template.
Use the following code
<template id="OrderReceipt" inherit_id="point_of_sale.OrderReceipt">
<xpath expr="//div[@class='pos-receipt-order-data']" position="replace">
<div t-esc="props.data.name" />
<div id="order-date" t-esc="props.data.date" />
</xpath>
</template>
This will remove the 'Powered By Odoo' Session from the pos receipt.
* Ensure your POS session loads the custom template by restarting the POS session and updating the assets.
Hope it helps