Text overlays: policy language people actually notice
Legal and ops teams want the same words on every page: CONFIDENTIAL, DRAFT, NOT FOR DISTRIBUTION, or © Year Company. This spoke is that string, not a logo. pdf-lib draws the glyphs as an overlay so underlying text stays selectable. Rotate a few degrees so the line crosses body copy and is harder to crop out of a single paragraph. Opacity 25–40% is typical for confidential review; lighter for a copyright footer people should still be able to ignore while reading. All-caps reads at thumbnail size; a long legal paragraph as the overlay will wrap poorly — keep it to a few words. Instant processing is local. Huge files and true multi-file queues need Premium. This is not encryption. If the PDF is already a scan (image-only pages), the overlay still sits on top; OCR is a different product.
When to use this spoke instead of the hub
Use the hub if you might pick a logo. Stay here when the brief is literally a status word or copyright notice. Switch to the business spoke for contract/invoice context.
Typography that survives print
Avoid hairline fonts. A bold sans at moderate size holds up on a cheap office printer. Preview, then print one page before a 200-page run.