Which data fields can I add to a form?
Only those fields that are available for a particular form can be used on it. The list of fields and columns available for each form appears in that form's Select from List window. These are the only data fields that can be added to that form. (To add data fields to a form)
You can use copy-and-paste features to copy fields from one form to another, but you cannot copy data fields from form to form unless the fields that you want to copy are available on both forms. For example, you can copy the Sale Status field to and from any invoice, since that field is available on every invoice form layout. You cannot, however, add a Purchase Status field to any invoice because that field is available only on purchases.
Elements (including all available text and data fields) can be placed in forms by adding them to the form layout or by copying them from other parts of the existing layout. (To copy elements on a form)