Signal is working on a way to sign up without a phone number. The feature has not yet been officially confirmed, and it is not yet known whether it will be available to all users or in what form.
No, apps (at least on Android) require a specific permission to read your phone number. The phone capabilities of Signal go through their own VoIP service, not your phone.
No, apps (at least on Android) require a specific permission to read your phone number. The phone capabilities of Signal go through their own VoIP service, not your phone.