I don’t know. I signed up with my email. A week or so before confirmation email they requested my phone number. When I was on Facebook I didn’t use my phone number because they made it public. That’s a big reason I left Facebook. You have to continually change your privacy settings because they keep changing them with out notice. Weird, Facebook owns Instagram but it’s not like that. On instagram you can have multiple accounts synced to your main account. Not visible by followers. Maybe Truth will allow that later.