The documentation for the latest stable version of the XForms library
is available in PDF and HTML format (the later as a gzipped tar
archive). You can download it as the files

xforms.pdf

and

xforms.html.tar.gz

The old documentation, originally meant for version 0.89 but useful
up to version 1.0.90, is available in PostScript format. The files to
download are

forms.ps.gz

which is suitable for printers capable of two-sided print (duplex).
If your printer can't, you should get

forms_sgnl.ps.gz