You may come across the situation, where you may want to give user level access to fields present on Screen.
In this case first create access code by navigating to below given path.
Setup → users → access code
Now assign this access code on required fields as shown below.
Now this fields are accessible to only those users whom “ZBPACS” access code is assign.
For example if access code is not assigned to particular user than that user is not authorized to create or update those fields.
Example:-