How to get the notification when the new user join?

[Kosuke Mineshima]

As the admin of Confluence, I'd like to receive the notification when the new user register to join our workspace of Confluence by email or some other ways. 
Could you let me know how to do that?  

[Monique Khairuliana[ServiceRocket]]

In Cloud, I think it should give admins notifications by default. Try checking if this setting is enabled:

With the Email site administrators when a new user gets access to the site checkbox, you can also choose whether site admins should receive an email when a new account gets access.

Got from this documentation: Specify how users get site access