Accessible PDF tagging is the hands-on remediation work behind PDF accessibility: opening a PDF in specialized authoring software, building or correcting its tag tree so headings, paragraphs, lists, and tables are properly marked up, fixing reading order so content flows logically, adding alt text to images, and correctly labeling any interactive form fields.
This work is often more time-consuming per document than typical web remediation, particularly for scanned documents that need OCR text recognition first, or for complex tables and multi-column layouts where establishing a correct, logical reading order takes real manual judgment.