Convert ODT to PDF

No — this conversion pins the layout. An ODT adapts its line breaks to whatever width and font size the reader is using; the PDF fixes page geometry at conversion time, so on a phone you get the whole page scaled down rather than text rewrapped to the screen. That is the right trade when the layout must not move, and the wrong one when the file is for reading on a small device. ODT is the mandated format in several national and EU public administrations and carries no vendor lock-in. PDF is Adobe’s Portable Document Format from 1993, standardised as ISO 32000 and now the universal fixed-layout document.

Not the way you edit the ODT. The PDF is a delivery format: it fixes the layout so it renders identically everywhere, which is exactly why it resists editing. Keep the ODT as the working copy and regenerate the PDF whenever the content changes — round-tripping back out of PDF always loses something.

Body text, headings, lists and simple tables move across cleanly in both directions. The known casualties are the same ones LibreOffice has always had: tracked changes, comments anchored to ranges, footnote numbering schemes and nested table borders. Check those specifically rather than assuming the whole document made it.

Yes, and the ODT would not have. Browsers ship a decoder for PDF and none for ODT, so an ODT link forces a download while a PDF renders inline. That is usually the deciding factor when the file is going onto a web page rather than into an application. A PDF looks byte-for-byte identical on every machine and every printer, which is why contracts, invoices and academic papers all live in it.

Not in this same step — convert ODT to PDF first, then use /pdf-protect/ to add an open password, owner password, or print / edit restrictions. Splitting the steps lets each conversion stay focused and fast.