How to send the registered user email to SalesIQ so that the user does not have to enter the email again when initiating a chat.

How to send the registered user email to SalesIQ so that the user does not have to enter the email again when initiating a chat.

I use SPA for my business and whenever users chat with me they always need to enter their email.
I would like to know if there is a way to automatically fill in the emails of registered users?

I've checked the documentation and it seems that only the API is provided and after many attempts I can't use the APi.

I would like to know how I should configure it using JS (code below)? For example in Index.html?

window.$zoho.salesiq && (window.$zoho.salesiq.ready=function()
                                    { $zoho.salesiq.visitor.name("User");
                                      $zoho.salesiq.visitor.email("Email");
                                    }),

Thanks