I know this is an old post, but I just wanted to chime in since I recently dealt with a similar issue. To add phone number authentication, you'll likely need to edit the backend files, mainly the ones for user registration and login—typically in the auth or user controllers. You’ll want to integrate an SMS service to handle the verification process. For me, Tardigrada.io worked great because they allow you to use a non VOIP number for authentication. I had a few bumps along the way, but their support was really responsive, and it ended up being pretty smooth.