1. From Setup, click Manage Users -> Profiles or Manage Users -> Permission Sets.
2. Select a profile or permission set to change the field access for users assigned to that profile or permission set.
3. Depending on which user interface is being selected :
• Permission sets or enhanced profile user interface :-
In the Find Settings, Enter the name of the object you want and select it from the list. Click Edit, then scroll to the Field Permissions section.
• Original user interface :-
In the Field-Level Security section, click View next to the tab you want to modify, and then click Edit.
4. Specify the field's access level. The setting labels may differ depending on which user interface is being used.
5. Click Save.