Depends on 1) the construction of the page, and 2) the PDF distiller, whether that is a third party add-on, or native to the OS.
Some sites, including many major ones (like UPS) pay little to no attention to how their pages look if users attempt to print them, so the way they construct their pages make the results look unpredictable, if not crappy in any case, though trying different browsers may yield acceptable results. There are also extensions that can manually eliminate page elements to help.
Mac OSX, which originally relied on Display PostScript for its graphics rendering, has supported native printing to PDF as a system-wide function since the beginning, as well as third-party options ike Adobe Distiller.
Windows users have had to rely on Adobe, or other third party options for a long time, but I think MS finally added its own native capability since Win10, IIRC.
The browser in question isn't specified, but IME, Firefox's print system has always lagged behind others, though it has made strides in recent times. When I don't get good results, I try another browers.
However, one nicety it has added recently is the ability to capture screenshots, including the full unbroken page, and excluding the chrome, and save them to an image file.
Since it's captured as an image, that does sacrifice the links, text, and discrete images, and other page elements, but it does still represent a page in its entirely. That file can be printed to PDF, which will embed that image as a graphic, perhaps at some loss in fidelity, but does offer another format option.