Hi Pedro,
Email notifications are actually sent to SU01 maintained Mail IDs for approvers and Email ID maintained in the request form for end users.
Stage Notifications are triggered when the request go to that stage or actions on that stage are completed.
Eg: New Work Item, Approved etc
Global Notification Settings are triggered once the request approval is completed i.e., at the end of the request and also during request Submission which is initial start of all requests.
Eg: Submission Event, Closing Event
Regards,
Madhu.