I have a wizard created form in libreoffice base with a subform. The data attached to the “base” form is shown when exported in PDF format. However, the subform data is not. The subform control (a table) is shown, but the data it contains is not .
If you want to print a form in those conditions it could be better you copy the whole window and paste it in a writer document.
To get printed documents from a database you should use a report not a form or combine data with a writer text (similar to mail merge).
Bye!