In webforms, how do I send the current user an email automatically? I'm trying to send an email to the logged in user who filled out the form without having them enter their email.

The form is made with webforms 8.x-5.x which has a lot of functionality.

I've only tried doing it non-programmatically through the interface by adding an email and using the "custom to email address" where i attempted to use the token: [current-user:mail] which did not work.

I've made a separate email handler for anonymous users, which just uses the email they fill in.
As @huelfe recommended, the token [webform-authenticated-user:mail] actually works for this purpose in the custom to email address.