Organise on the thumbnails
After you open a PDF, every page has Rotate, Up, Down and Delete buttons, and you can also drag thumbnails into place. Checked pages are included in the output; unchecked pages are left out.
Check the new order
After you rearrange, the page numbers shown follow the new order. Rotation is in 90° steps and does not turn text into images. If you make a mistake, choose the original file again — its contents were not overwritten.
Check the result
Download the new PDF and check the order and orientation. Keep the original: deleting, reordering and rewriting pages affects original digital signatures, and bookmarks, forms and attachments are not guaranteed to be kept.