Firebase Auth Inivite Only Scheme : How to communicate the credentials to user?

Here's my question. To access our app, the users must be invited.

This means, we use an admin web app to create the user account in Firebase and we send him an invite to download the app and use it.

Now the next phase, how can we send to the newly created user his credentials?

Our first idea was to use a temporary password. We could send the password by email to the user and ask him to redefine his password at his first logging.

His this a good idea? I guess it's not

Is there a better way?

Thanks for the help. T