Email notifications

Hi Team,

I would like to understand how system-generated notifications (Journeys, Goals, Performance, Helpdesk, and BIP Bursting) are sent to employee emails in these scenarios:

Employees with both Personal and Work Emails, but the personal email is primary
Employees with both Personal and Work Emails, but the work email is primary
If only a personal email exists, but no work email
If only a work email exists, but no personal email

Thanks.