Converter
Tag Your Untagged PDF
"Document is not tagged" is the #1 accessibility failure. This adds the full tag layer to the PDF you already have.
Tags are the hidden skeleton of an accessible PDF — the machine-readable outline (headings, paragraphs, lists, figures, tables) that screen readers walk instead of the raw ink. Most PDFs ship without any: the export setting was off, or the generating tool never wrote them. Adding tags afterward by hand in Acrobat is slow, fiddly expert work — which is what per-page remediation services actually bill you for. Ceereo automates it for born-digital documents: content analyzed, roles assigned, reading order sequenced, furniture marked as artifacts, and the whole tag tree threaded into your original file with a pixel-diff proving nothing visible moved.
Pixel-identical output Minutes per document Try without signing up
Last updated: August 6, 2026 · Reviewed by the Ceereo team
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How it works
How to tag your untagged pdf in four steps
The fastest way to tag your untagged pdf without manual copy-paste, screenshots, or formatting cleanup.
- Step 1
Upload your Word document
Drop in the messy .docx you want cleaned up. Your file is processed only to format it and is never used to train models.
- Step 2
AI reads the structure
The AI detects headings, body text, lists, and tables, and finds inconsistent styling, without changing any of your wording.
- Step 3
Formatting is fixed
Heading styles, alignment, spacing, fonts, lists, indentation, and margins are made consistent across the whole document.
- Step 4
Download the clean .docx
Get a still-editable Word file that opens in Microsoft Word, Google Docs, and LibreOffice: clean formatting, your words unchanged.
In short
An untagged PDF has no machine-readable structure, so screen readers get raw ink order — the single most common accessibility failure. Tagging adds the hidden outline (headings, paragraphs, figures, reading order). Ceereo writes that tag layer into your existing born-digital PDF automatically, visually unchanged and machine-verified.
What are PDF tags and why do they matter?
Tags are invisible structural labels — Heading 1, Paragraph, Figure, Table — arranged in reading order inside the PDF. Assistive technology navigates by them: jump between headings, read cells by column, skip decorations. Without tags a screen reader can only guess from raw drawing order. Tagging is therefore the foundational fix; nearly every other accessibility repair builds on it.
The foundational fix
Everything else stands on the tags
Alt text needs a Figure tag to live on; reading order is the sequence OF tags; heading navigation is the tag tree. That's why 'document is not tagged' outranks every other finding — and why fixing it first collapses most of the rest of your audit.
Features
Why teams choose Ceereo for tag your untagged pdf
Full role assignment
Headings by level, paragraphs, figures — assigned from real layout analysis.
Artifacts handled
Repeating headers/footers marked so readers skip them — a detail hand-taggers often miss.
Original file preserved
Tags are inserted into your PDF's existing content — pixel-diff verified.
Use cases
Where tag your untagged pdf works best
The classic failure
Checker said 'not tagged' — this is the direct fix.
Legacy libraries
Years of published untagged PDFs, fixed per document instead of per page.
Toolchain gaps
Your generator (or print-to-PDF) never writes tags; repair after the fact.
Why not just copy-paste?
Ceereo vs. doing it manually
Fixing formatting by hand takes ages and rarely comes out consistent. Here's the difference.
Output quality
What the cleaned document looks like
Every tag your untagged pdf run produces a tagged, machine-verified PDF that is pixel-identical to your original. Here's what you get.
- Complete tag tree: structure elements + reading order + artifacts
- Metadata repaired: language, title, viewer preferences
- Machine re-verification included
- Visually identical output, proven per page
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Frequently asked questions
How is this different from Acrobat's Autotag?+
Same category of operation — automated tagging — but self-serve, verified (machine re-check + pixel-diff shown to you), priced per document, and honest about inputs it declines (scans, forms) instead of tagging them badly.
Do tags change file size or compatibility?+
File size grows slightly (the structure data); compatibility is unaffected — tags are part of the PDF standard and invisible to normal viewers.
My PDF is a scan — can you tag it?+
No — a scan has no text to tag; it needs OCR reconstruction first. The tool detects this and says so rather than producing junk tags.
Add the missing tags
Upload your untagged PDF; download the structured, verified version.