Settings \ Organization \ Field Settings
You may also select the Field Settings Tab to hide/turn on/off Fields related to Cases, Items, or Persons.
Hiding fields will prevent them from being shown on any screens in your Organization.

Clicking the Case drop-down will reveal Case Fields you may wish to hide from view.

Clicking the Item drop-down will reveal Item Fields you may wish to hide from view.

Clicking the Person drop-down will reveal Person Fields you may wish to hide from view.

* Scenario 1 * - You wish to hide Make/Model/Serial # from ALL Items during the initial Item Entry process, and instead create your own Make/Model/Serial # Custom Data Form and attach it to Only Items you choose to streamline the Item Entry process.
If you've entered any data in the original Make/Model/Serial # fields, that data will need to be copied into the new Make/Model/Serial # Custom Data Form fields and then the original Make/Model/Serial # fields may be hidden, leaving only the new Make/Model/Serial # Custom Data Form attached to Only Items you choose.