You could potentially use a notificationHandler?
RecordSubmittedNotification
RecordApprovedNotification
RecordRejectedNotification
RecordSavingNotification
RecordStateChangeNotification
Another way is to wait until the successmessage/page is seen, you can get the recordId from the tempdata.. and delete then?
Thought this could be a little fraught with danger.. As if any workflows executing out of process you might be deleting the record before it’s still needed?
Perhaps a daily cleanup of records might be better? There’s something out of the box…
Umbraco Forms scheduled record deletion task will not run as it has been not enabled via configuration. To enable, set the configuration value at 'Umbraco:Forms:Options:ScheduledRecordDeletion:Enabled' to true.
Configuration | Forms | Umbraco Documentation
If I’m reading your use case, you probably want to DisableRecordIndexing too.
Though I have to say only retaining data in emails for the client is also dangerous as then you have a single point of failure non-delivery of email for whatever reason and your lead is gone!
If it’s a data protection issue, then you have sensitive data fields if you want to restrict who can view what.
Also nothing worse than a shared inbox means multiple emails sent to the end user by the client rather than embrace the forms backoffice for a workflow of submitted → approved if one of the team already dealt with it.
Also ideally if this is high traffic and you want to see the end user get a success message as fast as possible the ideal is to take the actual email sending out of process and add to a message queue.