PDF export
Readers can save any docs page as a PDF, for reading offline or sending to a colleague. There is nothing to set up: every page has it, on every plan.
Saving a page
Choose Save PDF among the actions at the top of the page. It opens your browser's print dialog, where you can pick Save as PDF as the destination.
Printing the page yourself works too, with Ctrl+P or Cmd+P.
What it looks like
The PDF is made for paper. It always prints in the light theme, whichever one you're reading in. The sidebar, top bar and page outline are left out, and code blocks are shown in full rather than cut off at their scroll height.
One page at a time
This saves the page you're on. There is no export for a whole site.