Contact users
Users can be contacted at their primary email address or primary phone number.
They can have more than one registered email addresses, but only one of them will be their primary email address. Same thing with phone numbers; they can have more than one, but only one will be their primary.
Clerk takes care of automatically assigning a verified email address or phone number as the user's primary contact method, but users are allowed to pick one through their account settings as well.