Is there a means to secure the Generic Text that can be entered in various applications?

We have a need to secure the Generic Text/Notes entered for Items, Suppliers, Customers, transactions and Credit. Most all users should be able to review the notes but only certain users should be able to revise, delete a line, or the entire note. The function key edits sort of work for the delete a line and delete all but cannot appear to prevent changes or completely blanking out a line of information. Are there any other techniques or provisions for protecting the Generic Text?

George....