queXF forms are creating using queXML. A questionnaire is designed in XML, then exported to a PDF file using the queXML stylesheets, or queXMLPDF class.
The fastest way to get a form ready to use with queXF is to use Limesurvey or queXS. These allow for the web based creation of questionnaires, and for them to be exported as a queXML PDF file with associated banding information. These can be directly imported in to queXF.
Also, see the documentation section of the queXML website for more information about creating forms.