Identify which PIN instructions you are following
An old tutorial describing a local-network-only PIN is not describing Emby’s current Profile PIN. The official password guide says the older mechanism, used before server version 4.8.x, has been replaced. Before troubleshooting a missing prompt, record the server version, the client device and whether the user has already authenticated on that device.
Set the user PIN and enable its use on the device
Emby normally authenticates a user once on each device and remembers those credentials for later profile switching. The optional Profile PIN adds a check when returning to an authenticated profile on a shared device. Its field accepts four numeric digits. The documented setup has a second part: when the user first authenticates on each device, answer Yes when the app asks whether to enforce the PIN for subsequent access.
Verify the return-to-profile behaviour
For example, a household may have both a lounge television and a tablet with the same adult profile. Completing the prompt on the television does not describe what was selected on the tablet. Check each shared device deliberately by switching away from the intended profile and returning to it. Keep the account password available to its owner and distinguish that initial authentication from the later PIN prompt in your notes. If the expected prompt is absent, report the actual setup sequence and client version rather than assuming that every PIN field or remembered login behaves identically.
Questions, answered
Is setting the Profile PIN field the whole documented setup?
No. The app also asks whether to enforce that PIN when the user first authenticates on each device.