SVG is refused by most social networks, marketplaces and document editors. PDF looks the same on every device and keeps several pages in one file. SVG is at home in logos, icons and illustrations that must scale; PDF is the usual choice for documents that must look the same everywhere, and printing.
Add several files and you can also combine them into a single PDF. The defaults suit most files. Under Options you can choose the page size.
The SVG is drawn at its own width and height (taken from its viewBox if it has no size) times the scale set under Options, scaled down if that would pass 16,384 pixels a side or 64 megapixels. Scripts inside the SVG never run and files it links to are not fetched, so text in a font the SVG does not embed is drawn in a fallback font. Each picture becomes one page. The page can match the picture's own size or be A4 or US Letter; on paper the sheet turns to suit the picture, which is shrunk to fit inside the margins and never enlarged.