I’m sorry but I don’t understand what you mean, if you’re using a field value that is unique you don’t need to use any code to display that entry in the back-end when you search for it in the Entries list page.
If your goal is to display entries to users in the front-end, that’s not a Gravity Forms feature, you would need something like Gravity View: https://www.gravitykit.com/
Hey tasarla! If I’m understanding correctly, you’re looking for a way to allow users to search for entries in the frontend while keeping other entries hidden.
This article goes over a few methods of displaying entries in the frontend that might nudge you in the right direction.