Your form instances will be opened by different people at different stages of its life. You would not want to allow all users the same level of access to fields at all stages. For example, if you were to do that, applicants would be able to authorize their own requests.
With field state management you control access to individual objects on the form. You can prevent individual roles from changing, or even viewing, specific data or areas on the form. This section describes how to control access to fields based on a user's role and the workflow stage that the form instance is in.
For a demonstration of field access control using workflow stages and roles, see the Required Field Checking and Field States Example topic (available only in the online version of this help guide).