So far I've continued with my application thanks to rjcpjc who always answers back.
But here is the question to everybody:
When a client reaches certain status in my application (Application Sent, appointment, enrolled, etc), I want to turn on a field called "Locked" to "Yes" and restrict access to users to open(not view) this items. When a supervisor turns this field off, then the Items could be modified by the users. This is in a public folder. I Read about moderated folders but I don't think this is my solution, because I don't want to move the Items, I just want to make them "Read Only" based on the value of this field. Also, I don't know if permissions can be set to views specifically, I know about the roles for the folders and so on, but I want to make the custom view of a folder accesible to a certain group, the option "Make this folder visible only to me" does not make sense in this scanario. The Idea is to create a view containing this "Locked" field and if the user is a member of a group, then she could acces the view and change the value of this field, but the view in this folder would not be visible to the rest of the users.
Thank you very much