For example, you discover that the majority of the forms you are creating include a delivery address part. Instead of creating the delivery address subform in each new form, you copy the first delivery address subform you created and paste it into a separate XDP file. That way, you can easily copy the delivery address subform and paste it into the other forms that you create. When you have to change the delivery address part, either you make the change in every form, or you make the change in the separate XDP file and then replace the delivery address part in every form.
In LiveCycle Designer ES, these resusable parts are called
fragments, and instead copying the part from a separate file each time you need to use the part, you can insert a reference to the required fragment and the fragment appears in the form. Then, when you update a fragment, all forms that reference the fragment reflect the changes.