Hi,

The Widget tab on the live chat channel details form provides the shortcode for an embeddable website widget. This code can be added to a website to provide access to a live chat window.

The live chat widget can be added to websites created through Odoo by navigating to the Website ‣ Configuration ‣ Settings. Then scroll to the Livechat section, and select the channel to add to the site. Click Save to apply.

To add the widget to a website created on a third-party platform, click the first COPY button on the Widget tab and paste the code into the 

Likewise, to send a live chat session to a customer, click the second COPY button on the Widget tab. This link can be sent directly to a customer, and once they click the link, it will open a new chat.

For more:  https://www.odoo.com/documentation/16.0/applications/websites/livechat.html

Thanks