We are migrating our users to Auth0 database. When an user provided an email in the login page, we check if the user is existing user. If yes, we would like to create the user manually in Auth0 database and Auth0 then send Verification email. Question is how to mange the temporary password ? Is there a way to generate a code similar to passwordless feature and send in the content of the verification email? The user can then log-in in the redirected page with the code.
There are a couple of situations here worth discussing. Have you ruled out using a custom database with import mode as the method to perform the migration of users? This would allow users to be migrated while maintaining their existing passwords.
In the event that you don’t want to consider migrating users as above, I might be missing something, but even if you sent a code the first time, how would they login a second time. If you really want to start with some sort of clean sheet in terms of passwords would it not be better to create the user in Auth0 and then send them an email with a password reset link so that they can set their passwords.