How to store sent mail notification from any elm application?
One answer
I don't believe any ELM application archives what notifications are sent. I would not see that to be required and you do not provide a valid busyness case.
Anyway, the applications use a specific SMTP server configured to send the mail, so you could try to find out if your SMTP server has such a feature or if there are SMTP servers that can archive all mail they sent.