How add script tag to website?

This is my site

I wanna add below code to make a live chat button in corner let user interact
(To add a chat bubble to the bottom right of your website add this script tag to your html)

but cannot work, I ady try in embed code, custom code, and files js. Anyone know where I can add this?


Inside your admin panel (/admin) there’s custom code section, head (start/end), body (start/end) where you can paste any code snippet.