Write the new order as page numbers separated by commas. You do not have to list every page: the ones you name come first, in the order you wrote them, and every page you did not mention follows them, still in its original sequence. Nothing is deleted along the way, so a forty-page file is still forty pages afterwards.
The PDF engine (about 500 KB) loads only when you drop a file in, so the page itself stays light. Your file is read on your own machine and never sent anywhere — open your browser's network tab and watch while you use it.
No. The pages you name lead, and everything you left out is appended after them in its original order. Typing 5, 1 on a twenty-page file gives you page five, page one, then pages two to four and six to twenty.
It is ignored rather than stopping the run — out-of-range numbers and stray text are dropped. If nothing you typed matches a real page, the tool says so and gives you no file at all, instead of a file in an order you did not ask for.
It appears twice. Every number you write places a copy of that page, so 1, 1, 2 starts the file with two copies of the first page. Occasionally that is exactly what you want; more often it is a typo, so read the list back before running it.
The pages themselves do — text, images, layout, all untouched. The outline panel does not: pages are copied into a fresh document, and bookmarks belong to the file rather than to its pages, so they do not come along.
These all work the same way — in your browser. Most are free; the ones marked as needing a plan are not.