When you create a new email in Google Admin Console, there is a field called Secondary email. This field will become a secondary work email after the user is created. This is a good place for inputting a user's home email address.
To automate sending a confirmation email, you can create a rule like this, User created trigger => Get user info action => Email action. In the Email action, add Secondary Work Email variable as the recipient email address. In this way, their home address will automatically receive the email notification after you create the work email for them.
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