Nothing to preview yet.
Your vault is already plain Markdown on disk, so a note can be converted directly. The wrinkle is that a few pieces of Obsidian syntax are not standard Markdown — here is what happens to each.
An Obsidian vault is an ordinary folder of .md files, which makes this simpler than it looks. Open the vault folder and drag the note onto this page. To copy instead, switch the note to source mode first — on the rendered view you will copy formatted text and lose the Markdown structure.
Obsidian adds several conveniences that only mean something inside Obsidian. Outside it they are just characters, so they need converting before the note leaves.
Obsidian prints through the same engine, but it prints the note as it appears in the app. Your theme, your custom CSS and your font size all come along, so a dark theme becomes a dark PDF and a comfortable reading width becomes an odd measure on A4. Here the document is laid out for paper from the start: you choose the page size, margins and typeface, and the preview shows the actual page rather than the app.
Every heading becomes a real PDF bookmark, so a long note stays navigable in a reader's sidebar instead of being one continuous scroll. Turn on Contents in the style panel for a linked table of contents at the front, and Title page to promote the note's title onto its own page. Both are useful for anything you intend to share rather than skim.
Open your vault folder in the file manager and drag the .md file onto this page, or switch the note to source mode, copy the text and paste it in. Then click Download PDF.
They stay as text, because they resolve against your vault and a PDF cannot reach it. Rewrite the ones readers need to follow as normal Markdown links with full URLs before converting.
A callout is a block quote with a marker line, so it renders as a block quote. The text and structure survive; the coloured box and icon do not.
No — Dataview builds them when you view the note, so the file itself only contains the query. Copy the rendered table out of Obsidian and paste it in as a Markdown table.