Add page numbers to a PDF

No. Toolpit does not upload your file for processing — the tool runs as code in this browser tab, works on the copy your browser opened, and forgets it when you close the tab. You can check this yourself: open your browser’s network panel and run the tool. You will see the page, its scripts and the ads on the site, and — when you save, if you are signed in — one small request that charges 10 tokens to your account. None of them carries your file, its name or anything read from it, because file processing stays on your device.

Put "2-" in the pages field. The cover is left clean and numbering begins on page two — and if you want that page to still read "1", set Start at to 1.

You can, but you will end up with two sets. If the existing numbers are wrong because pages were merged or reordered, the usual fix is to place the new number in a different corner so it is clearly the authoritative one.

Yes. The position is worked out per page from that page’s own size and rotation, so a landscape page in the middle of a portrait document still gets its number in the corner you chose.

Yes — set the starting number, which is what you want when the document is a chapter of something larger, or when a cover and contents pages should not count. You can also begin numbering from a later page so the cover itself stays clean while the numbering still reads correctly from there on.

They are drawn in the margin at the position you choose, which on an ordinary document is empty. A page already carrying a footer, or one scanned so tightly that the text runs to the edge, can collide — the live preview is there to catch that before you download. Moving the number to the opposite corner usually resolves it.

Not cleanly: they are drawn into the page as ordinary content, exactly like the rest of the text, so there is no separate layer to peel off. Keep the original file. That is the honest answer for any tool that stamps a PDF, not a shortcoming of this one.