Hello,

The Chat button functionality on the Site right now isn’t available from Theme end so you might need to use a third party Plugin in this regard that best meets your needs.

You can check out these third party website Articles in this regard if they are of any help:

https://www.wpbeginner.com/wp-tutorials/how-to-add-a-free-live-chat-in-wordpress/
https://www.wpbeginner.com/showcase/7-best-live-chat-support-software-for-your-wordpress-site/

Note: Remember we cannot take any guarantee for 100% compatibility and smooth working of the said Plugins on this Article. This is just for your reference and ease. Hope you can understand !

Best Regards