IconVault's PDF Toolkit is a five-in-one PDF editor that works without uploads or installs. Merge multiple PDFs into one in any order, split pages out by ranges like 1-3, 5, rotate selected pages by 90, 180 or 270 degrees, add a text watermark (diagonal, centered or corner, with adjustable opacity and size), and reorder pages with simple up and down controls.

Every operation runs fully in your browser with pdf-lib, so your documents are never uploaded to a server and the tool stays free to use. The honest caveat: encrypted or password-protected PDFs cannot be opened here, so remove the password protection first in another app before loading them.