It is strongly recommended that you should not change anything for a standard entry. This may causes a big problem for your organization.
Todd has already shared a screen shot of F-02 (which is standard), revert back the F-02 t-code as per the screen shot.
And then, as per your requirement, you want to set a field as display mode, A field can be set as display/required/optional/hide from these below methods:
1. Transaction variant from SHD0 (I have already provided you in your previous discussion)
2. By screen layout. (It can be differ for different transaction)
3. By using your own development / enhancement (user exit / badi).
