Types of PDF Forms

There are two (or three) types of PDF forms: AcroForm and XFA (static and dynamic):

•  Acroforms are the traditional, most common type of PDF forms;  These can be created using Adobe Acrobat.
• Static XFA PDF forms contain an XML stream that contains the form field information, as well as the traditional PDF (Acroform) structure describing form fields.  These can typically be opened and processed by the non-Adobe viewers or tools, as long will utilize the traditional PDF Acroform structure, rather than the XFA. 
• Dynamic XFA PDF forms are just an XML stream wrapped in a PDF shell. They allow a PDF form to be dynamic (the Acrobat / Reader display changes based on the fields/buttons selected). These files are created by Adobe LiveCycle Designer now AEM Designer, but usually cannot be viewed or processed by non-Adobe viewers such as Chrome or Safari. In that case, the viewer may display the placeholder content which is usually a warning to upgrade or use Adobe Reader.

 XFA (static and dyamic) PDF Forms are created by Adobe AEM Designer (previously LiveCycle Designer), typically as part of a form workflow in conjunction with Adobe AEM or LiveCycle Server installations often used by government and large enterprise companies