Someone else uses this phone too. Will they see my prompts?
Signing out deletes your app lock and your notification registration from that handset, and whoever signs in next sets their own lock. While you are signed in, your prompts go to you.
From the guide Approving Sign-ins on Your Phone.
Your PIN never reaches Seayora
The PIN or pattern is stored only on that phone, in the platform’s own secure keystore (the Android Keystore or the iOS Keychain), and it is checked on the phone. It is never sent to Seayora, we cannot see it, and we cannot reset it for you — if you forget it, sign out of the app and sign back in with your password. What the account does record is that a lock exists on that handset and which kind it is, so your security settings can tell you which of your phones is protected.
Your face and fingerprint never reach Seayora either. The app asks the operating system whether it is you and receives yes or no; the biometric data itself never leaves the device’s secure hardware and Seayora has no access to it.
Read the whole guide: Approving Sign-ins on Your Phone