The System Administrator can set up field security for the whole CRM system, for individuals, teams, and for security profiles via the Administration | Customization | <Entity> | Fields tab.
For example, it is possible to make a field invisible to some users, allow others to view the contents of the field but not to change them, and to give others both read and write rights. In addition, it is also possible to make it mandatory for the user to enter a value
in the field before submitting the form. For more information on Field Security please refer to "Using Field Security", in Chapter 14 of this guide.
Access rights set for Everyone, an individual user, and a security profile