Auth0 only supports emailing users for the different email template use cases. Other scenarios involving sending emails, would need to be carried out outside of Auth0.
If all users in a tenant need to be emailed for a specific reason, it is recommended to perform a user export to retrieve the users’ emails from Auth0’s records. You can use the exported file to create a distribution list and then call the chosen Email Provider’s APIs to send the desired email. By using the “fields” parameter when calling the bulk export endpoint, you can set the email as the only exported detail about the users, making it easier to generate a distribution list. For additional information, refer to the Bulk User Exports documentation.