Biometric authentication checks identity with a body trait: a fingerprint, a face, sometimes an iris. The phone or laptop compares the scan with a template stored on the device. The person does not type a password they reuse on other sites.
It is not the same as a passkey. A passkey is a cryptographic credential. Biometrics often unlock that passkey, or the device. The scan itself is not the credential websites store. Two-factor authentication is a second check — a code, an app, a key — which might be biometric and might be a text message. The session still needs HTTPS and SSL. At checkout, a face scan can finish a payment that a forgotten password would abandon. A selfie uploaded to a random form is not the same protection as a device-bound scan.
A real-life example of biometric authentication
A Decatur retailer offers a wallet payment at the counter. The customer glances at the phone. The face scan approves it. They never create a store password. That is a biometric unlock of a payment credential — harder to phish than a reused password, and faster than an account form. A website that only says “email us a photo of your ID” is not offering the same thing.
Use the device’s own scan for the moment that matters, and keep a backup sign-in for when the sensor fails. Background: biometric authentication UX and passkeys vs passwords.