Marking a document DRAFT or CONFIDENTIAL before it circulates is a small thing that prevents a large class of misunderstanding.
Add text or your own logo, set the opacity and angle, and choose whether it sits behind or over the content. There's a certain irony in most free watermark tools adding their own watermark to the output; this one doesn't.
Placing it behind the content keeps the document readable, which is what you want for DRAFT or a company logo. Placing it over the top at low opacity is harder to ignore, which is what you want for CONFIDENTIAL or DO NOT COPY. You can also restrict it to particular pages, so a cover sheet stays clean while the body is marked.
As with page numbers, the mark is drawn into the page content rather than attached as an annotation, so it survives printing and can't be clicked away by the recipient's PDF reader.
Combine files into one PDF and set the order before you merge.
Break a document into separate files by range or interval.
Drag pages into a new order, rotate or drop the ones you don't need.
Turn sideways or upside-down pages the right way up.
Pick pages to drop, visually or by range.
Keep only the pages you want as a separate file.
Combine JPG or PNG images into one PDF, with page size control.
Render pages to images at the resolution you choose.
Shrink a PDF with a side-by-side quality preview and a size target.
Add a searchable text layer to a scanned document.
Extract text as plain text or Markdown, in reading order.