When you create a form you can set certain permissions on fields:

• Employee cannot view or update, so this should mean it will be visible to HR access level users and the employee’s manager.
• Employee can update field, the employee and their manager as well as HR and Admin access level users can update this field
• Employee can update field, manager cannot update field
• Employee can view only, they cannot update the field
• HR Only, only HR and Admin access level users

By default, only Field display label, Mandatory field and Field type are accessible. To access the Field access option, move the Show advanced options switch to the right 

With Show advanced options turn on you can also see the Database field name and Clone field options as well as other options including the Field access option.

Click here for more information on Cloned fields

Here some Field access permissions set for a Performance review form, in this example the Employee will not be able to even see let alone update 3 and 4.

When the Employee logs in and accesses the form, options 3 and 4 are not visible and the Employee cannot update the Date option

However, when their Manager accesses the same form, they can see all 5 fields/options and can update the Date option

These permissions can apply to different field types including Date, HTML, Accordion and Text.