replied on February 13, 2015
Hi Dominic,
It is possible to use CSS to change the form's orientation to landscape within Forms, but retaining that orientation when converting it to a tif or pdf in the Client is not currently supported. If you can provide more details about this use case (preferably an image of the form if you're comfortable with that, but otherwise some information detailing its current layout, why it's so wide, its use, etc.), I can pass the information along to the Forms development team as a feature request.
In the meantime, there may be a few form settings you can modify to alleviate the issue. To help narrow the width of the fields and lengthen the form, it's possible to set the field labels to reside above the fields rather than beside them. This is configurable in Form Settings under Labels. Field widths are also adjustable in each field's settings, and character limits can be set. Finally, adding CSS or JavaScript to the form will give you more extensive means of changing the layout.