How to add page numbers to a PDF on iPhone
- Open the document in ScanLens — a scan you made, or a PDF you imported.
- Check the page order first. Numbering follows the order the pages are in, so fix that before you number rather than after. See reorder PDF pages.
- Tap More → Export and keep the format as PDF.
- Turn on page numbers and choose how they look: the numbering style, where on the page they sit, and whether to include the total.
- Export. The numbers are drawn onto every page of the exported PDF, so they travel with the file wherever it goes.
The numbering lives in the exported copy, not in the document you keep. Export again without it and you get a clean version — useful when the same scan goes to two places with different requirements.
Why numbered pages matter more than they sound
Page numbers are one of those details nobody notices until they are missing, and then they cost everyone time.
They make a document referable. "The clause on page 7" only works if there is a page 7. Any document that will be discussed rather than just read — a contract, a report, a submission — needs them.
They prove nothing is missing. A numbered set with a total is self-auditing: page 9 of 14 tells the recipient exactly what they should have. This matters most for documents that get printed, posted, or handed across a desk, where pages genuinely go astray.
They survive reprinting. A file that gets printed, signed, scanned again, and emailed back keeps its numbers through every one of those steps, because they were drawn onto the page rather than added by a viewer.
Scanned documents are exactly the case where numbers are usually absent: the pages were never numbered on paper, or the numbering restarts partway through because the bundle came from three sources.
When the pages already carry numbers
If the original paper was numbered, adding a second set produces two sequences on the same page, which is worse than none. A few ways that plays out:
The printed numbers still match
Nothing to do. The document already refers to itself correctly.
They match but sit where yours would
Move the new numbers to the opposite corner, or the top, so the two do not overlap and it is obvious which is which.
They no longer match the bundle
This is the common case with combined documents: three sources, three sequences, all starting at 1. New numbers over the top give the bundle one coherent sequence, and including the total makes clear which one to trust.
Some pages are missing
Fix the set before you number it: remove pages that do not belong, and merge what should be one document, then number the result.
Numbering a bundle assembled from several documents
The most useful case for numbering is also the messiest: a submission or claim built from a scanned form, a photographed receipt, an emailed PDF, and a signed page. Assembled, it is one document to the recipient and four to you.
Get the sequence right before numbering. Merge them into one file, put the pages in the order the recipient expects, drop anything duplicated, and only then export with numbers and a total. The result is a single file where page 11 of 18 means the same thing to both of you — which is exactly what an office asking for "the documents" wants, rather than four attachments they have to collate.
Sending several documents as one PDF covers the assembly step in full.
Doing it on a computer instead
Desktop tools handle this too, and if the document is already open on a computer there is no reason to move it. Acrobat adds numbering through its header and footer tools, with control over which page the sequence starts on. Word applies numbers when the document is exported to PDF. Online tools do it in the browser, at the cost of uploading the file to somebody else's server — worth a thought for anything sensitive.
The phone wins where the document was created on the phone. A stack of paper photographed on the kitchen table can be scanned, ordered, numbered, and sent without the file ever touching a computer.
