Your records are stored online, not only on the iPhone.
New users are Operators. An Administrator can edit/delete records. Operators can add and view records but cannot edit/delete.
To promote a trusted user, change their role to admin in Supabase → Table Editor → profiles.
ONLINE v3 — Configure the database before signing in.
Paste your Supabase Project URL and Publishable key. Never use a secret/service-role key here.