Short answer
In Google Docs you can use File → Download → PDF directly. If you have a .docx exported from Google Docs (File → Download → Microsoft Word) and want a PDF, drop it here — it converts in your browser with nothing uploaded.
Google Docs' built-in PDF export is the simplest route when the document is already in Docs. This tool helps when you've downloaded a .docx and want to turn it into a PDF without re-uploading it anywhere.
Structure and text are preserved so the PDF stays selectable and searchable.
Yes — File → Download → PDF Document. Use this tool when you only have the downloaded .docx.
Headings, paragraphs, and lists are preserved; very complex layouts are simplified.