If you do not want an additional detail field to be displayed when adding a new vehicle, you can inactivate it or delete it. However, you cannot delete an additional detail field that has already been used to record vehicle information.
At the top of your dashboard, click the module access icon > Administration > Transport > Manage vehicle additional details to open the Manage vehicle additional details page.
Click Edit beside the additional detail field you want to edit, select the Inactive status, and then click the Update button. Additional detail fields that are inactivated are moved under the Inactive fields list.
Click Delete beside the additional detail field you want to delete.
For more information, view this :