If you would like to delete fields for your custom form you can easily do so from your control panel. In the same way you can add additional fields to your form, you can also remove any fields you do not wish to use.
To begin, click on the icon for forms and choose form editor.
Click on your selected form name to access your form fields.
Click on the pencil icon next to any form field to access the form settings.
From the drop down you can choose the option for delete to remove your selected field.
You can also choose to make a field required from the same drop down menu. This will require that your client complete the required field before they can submit the form.