[Design The PDF Layout] The design looks dramatic, but the layout is quite simple. It has only one column, which contains all the questions, in one text frame, on the left. The half-column on the right contains some information in a text frame. The headline and the Name, Address, etc, are in a text frame that spans the entire width of the page. The colored bands to mark the sections are obviously colored rectangles drawn behind the section sub-heads. The logo in the background is just the flame from the 'inflammable' SVG graphic. This time it is colored to Red at 20% shade. It is kept on another Layer stacked at the back.
[Clickable PDF Elements] The real questions are, how are the text fields, number fields, check buttons, and 'submit' button drawn that they work interactively inside Acrobat Reader or other PDF viewer programs? Use the special PDF tools in Tools>Toolbars>PDF Tools. Chances are you already have it open on your screen. An almost complete array of PDF elements can be authored in Scribus.
Once drawn, use the Properties palette for some cosmetic finishes. Then right-click the PDF element, and choose 'Is PDF Annotation' from the pop-up menu. Right-click again, and this time choose 'Field Properties.' You could also double-click the PDF element to configure it for PDF options. All PDF features are expressed here as screenshots. Enjoy.