How to filter data according to different users

[Peter_Krkoska]

Hi guys!
I am building an app, but I cannot find a way to solve one issue. The app users will not be signed in the app (I will not require sign-in), but I need to set up the app in a way that the specific user will see only his data. When the user fills the form in the app he types in his user number and I would need to use those user numbers to differentiate between different users so I can create charts for the specific users.

Any idea how can I resolve this issue?

Thanks in advance